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Hi; this pullreq contains only my FEAT_AFP/FEAT_RPRES patches
(plus a fix for a target/alpha latent bug that would otherwise
be revealed by the fpu changes), because 68 patches is already
longer than I prefer to send in at one time...

thanks
-- PMM

The following changes since commit ffaf7f0376f8040ce9068d71ae9ae8722505c42e:

Merge tag 'pull-10.0-testing-and-gdstub-updates-100225-1' of https://gitlab.com/stsquad/qemu into staging (2025-02-10 13:26:17 -0500)

are available in the Git repository at:

https://git.linaro.org/people/pmaydell/qemu-arm.git tags/pull-target-arm-20250211

for you to fetch changes up to ca4c34e07d1388df8e396520b5e7d60883cd3690:

target/arm: Sink fp_status and fpcr access into do_fmlal* (2025-02-11 16:22:08 +0000)

----------------------------------------------------------------
target-arm queue:
 * target/alpha: Don't corrupt error_code with unknown softfloat flags
 * target/arm: Implement FEAT_AFP and FEAT_RPRES

----------------------------------------------------------------
Peter Maydell (49):
      target/alpha: Don't corrupt error_code with unknown softfloat flags
      fpu: Add float_class_denormal
      fpu: Implement float_flag_input_denormal_used
      fpu: allow flushing of output denormals to be after rounding
      target/arm: Define FPCR AH, FIZ, NEP bits
      target/arm: Implement FPCR.FIZ handling
      target/arm: Adjust FP behaviour for FPCR.AH = 1
      target/arm: Adjust exception flag handling for AH = 1
      target/arm: Add FPCR.AH to tbflags
      target/arm: Set up float_status to use for FPCR.AH=1 behaviour
      target/arm: Use FPST_FPCR_AH for FRECPE, FRECPS, FRECPX, FRSQRTE, FRSQRTS
      target/arm: Use FPST_FPCR_AH for BFCVT* insns
      target/arm: Use FPST_FPCR_AH for BFMLAL*, BFMLSL* insns
      target/arm: Add FPCR.NEP to TBFLAGS
      target/arm: Define and use new write_fp_*reg_merging() functions
      target/arm: Handle FPCR.NEP for 3-input scalar operations
      target/arm: Handle FPCR.NEP for BFCVT scalar
      target/arm: Handle FPCR.NEP for 1-input scalar operations
      target/arm: Handle FPCR.NEP in do_cvtf_scalar()
      target/arm: Handle FPCR.NEP for scalar FABS and FNEG
      target/arm: Handle FPCR.NEP for FCVTXN (scalar)
      target/arm: Handle FPCR.NEP for NEP for FMUL, FMULX scalar by element
      target/arm: Implement FPCR.AH semantics for scalar FMIN/FMAX
      target/arm: Implement FPCR.AH semantics for vector FMIN/FMAX
      target/arm: Implement FPCR.AH semantics for FMAXV and FMINV
      target/arm: Implement FPCR.AH semantics for FMINP and FMAXP
      target/arm: Implement FPCR.AH semantics for SVE FMAXV and FMINV
      target/arm: Implement FPCR.AH semantics for SVE FMIN/FMAX immediate
      target/arm: Implement FPCR.AH semantics for SVE FMIN/FMAX vector
      target/arm: Implement FPCR.AH handling of negation of NaN
      target/arm: Implement FPCR.AH handling for scalar FABS and FABD
      target/arm: Handle FPCR.AH in vector FABD
      target/arm: Handle FPCR.AH in SVE FNEG
      target/arm: Handle FPCR.AH in SVE FABS
      target/arm: Handle FPCR.AH in SVE FABD
      target/arm: Handle FPCR.AH in negation steps in SVE FCADD
      target/arm: Handle FPCR.AH in negation steps in FCADD
      target/arm: Handle FPCR.AH in FRECPS and FRSQRTS scalar insns
      target/arm: Handle FPCR.AH in FRECPS and FRSQRTS vector insns
      target/arm: Handle FPCR.AH in negation step in FMLS (indexed)
      target/arm: Handle FPCR.AH in negation in FMLS (vector)
      target/arm: Handle FPCR.AH in negation step in SVE FMLS (vector)
      target/arm: Handle FPCR.AH in SVE FTSSEL
      target/arm: Handle FPCR.AH in SVE FTMAD
      target/arm: Enable FEAT_AFP for '-cpu max'
      target/arm: Plumb FEAT_RPRES frecpe and frsqrte through to new helper
      target/arm: Implement increased precision FRECPE
      target/arm: Implement increased precision FRSQRTE
      target/arm: Enable FEAT_RPRES for -cpu max

Richard Henderson (19):
      target/arm: Handle FPCR.AH in vector FCMLA
      target/arm: Handle FPCR.AH in FCMLA by index
      target/arm: Handle FPCR.AH in SVE FCMLA
      target/arm: Handle FPCR.AH in FMLSL (by element and vector)
      target/arm: Handle FPCR.AH in SVE FMLSL (indexed)
      target/arm: Handle FPCR.AH in SVE FMLSLB, FMLSLT (vectors)
      target/arm: Introduce CPUARMState.vfp.fp_status[]
      target/arm: Remove standard_fp_status_f16
      target/arm: Remove standard_fp_status
      target/arm: Remove ah_fp_status_f16
      target/arm: Remove ah_fp_status
      target/arm: Remove fp_status_f16_a64
      target/arm: Remove fp_status_f16_a32
      target/arm: Remove fp_status_a64
      target/arm: Remove fp_status_a32
      target/arm: Simplify fp_status indexing in mve_helper.c
      target/arm: Simplify DO_VFP_cmp in vfp_helper.c
      target/arm: Read fz16 from env->vfp.fpcr
      target/arm: Sink fp_status and fpcr access into do_fmlal*

In do_cvttq() we set env->error_code with what is supposed to be a
set of FPCR exception bit values.  However, if the set of float
exception flags we get back from softfloat for the conversion
includes a flag which is not one of the three we expect here
(invalid_cvti, invalid, inexact) then we will fall through the
if-ladder and set env->error_code to the unconverted softfloat
exception_flag value.  This will then cause us to take a spurious
exception.

This is harmless now, but when we add new floating point exception
flags to softfloat it will cause problems.  Add an else clause to the
if-ladder to make it ignore any float exception flags it doesn't care
about.

Specifically, without this fix, 'make check-tcg' will fail for Alpha
when the commit adding float_flag_input_denormal_used lands.

Fixes: aa3bad5b59e7 ("target/alpha: Use float64_to_int64_modulo for CVTTQ")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/alpha/fpu_helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/alpha/fpu_helper.c b/target/alpha/fpu_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/alpha/fpu_helper.c
+++ b/target/alpha/fpu_helper.c
@@ -XXX,XX +XXX,XX @@ static uint64_t do_cvttq(CPUAlphaState *env, uint64_t a, int roundmode)
             exc = FPCR_INV;
         } else if (exc & float_flag_inexact) {
             exc = FPCR_INE;
+        } else {
+            exc = 0;
         }
     }
     env->error_code = exc;
-- 
2.34.1

Currently in softfloat we canonicalize input denormals and so the
code that implements floating point operations does not need to care
whether the input value was originally normal or denormal.  However,
both x86 and Arm FEAT_AFP require that an exception flag is set if:
 * an input is denormal
 * that input is not squashed to zero
 * that input is actually used in the calculation (e.g. we
   did not find the other input was a NaN)

So we need to track that the input was a non-squashed denormal.  To
do this we add a new value to the FloatClass enum.  In this commit we
add the value and adjust the code everywhere that looks at FloatClass
values so that the new float_class_denormal behaves identically to
float_class_normal.  We will add the code that does the "raise a new
float exception flag if an input was an unsquashed denormal and we
used it" in a subsequent commit.

There should be no behavioural change in this commit.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 fpu/softfloat.c           | 32 ++++++++++++++++++++++++++++---
 fpu/softfloat-parts.c.inc | 40 ++++++++++++++++++++++++---------------
 2 files changed, 54 insertions(+), 18 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index XXXXXXX..XXXXXXX 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -XXX,XX +XXX,XX @@ float64_gen2(float64 xa, float64 xb, float_status *s,
 /*
  * Classify a floating point number. Everything above float_class_qnan
  * is a NaN so cls >= float_class_qnan is any NaN.
+ *
+ * Note that we canonicalize denormals, so most code should treat
+ * class_normal and class_denormal identically.
  */
 
 typedef enum __attribute__ ((__packed__)) {
     float_class_unclassified,
     float_class_zero,
     float_class_normal,
+    float_class_denormal, /* input was a non-squashed denormal */
     float_class_inf,
     float_class_qnan,  /* all NaNs from here */
     float_class_snan,
@@ -XXX,XX +XXX,XX @@ typedef enum __attribute__ ((__packed__)) {
 enum {
     float_cmask_zero    = float_cmask(float_class_zero),
     float_cmask_normal  = float_cmask(float_class_normal),
+    float_cmask_denormal = float_cmask(float_class_denormal),
     float_cmask_inf     = float_cmask(float_class_inf),
     float_cmask_qnan    = float_cmask(float_class_qnan),
     float_cmask_snan    = float_cmask(float_class_snan),
 
     float_cmask_infzero = float_cmask_zero | float_cmask_inf,
     float_cmask_anynan  = float_cmask_qnan | float_cmask_snan,
+    float_cmask_anynorm = float_cmask_normal | float_cmask_denormal,
 };
 
 /* Flags for parts_minmax. */
@@ -XXX,XX +XXX,XX @@ static inline __attribute__((unused)) bool is_qnan(FloatClass c)
     return c == float_class_qnan;
 }
 
+/*
+ * Return true if the float_cmask has only normals in it
+ * (including input denormals that were canonicalized)
+ */
+static inline bool cmask_is_only_normals(int cmask)
+{
+    return !(cmask & ~float_cmask_anynorm);
+}
+
+static inline bool is_anynorm(FloatClass c)
+{
+    return float_cmask(c) & float_cmask_anynorm;
+}
+
 /*
  * Structure holding all of the decomposed parts of a float.
  * The exponent is unbiased and the fraction is normalized.
@@ -XXX,XX +XXX,XX @@ static float64 float64r32_round_pack_canonical(FloatParts64 *p,
      */
     switch (p->cls) {
     case float_class_normal:
+    case float_class_denormal:
         if (unlikely(p->exp == 0)) {
             /*
              * The result is denormal for float32, but can be represented
@@ -XXX,XX +XXX,XX @@ static floatx80 floatx80_round_pack_canonical(FloatParts128 *p,
 
     switch (p->cls) {
     case float_class_normal:
+    case float_class_denormal:
         if (s->floatx80_rounding_precision == floatx80_precision_x) {
             parts_uncanon_normal(p, s, fmt);
             frac = p->frac_hi;
@@ -XXX,XX +XXX,XX @@ static void parts_float_to_ahp(FloatParts64 *a, float_status *s)
         break;
 
     case float_class_normal:
+    case float_class_denormal:
     case float_class_zero:
         break;
 
@@ -XXX,XX +XXX,XX @@ static void parts_float_to_float_narrow(FloatParts64 *a, FloatParts128 *b,
     a->sign = b->sign;
     a->exp = b->exp;
 
-    if (a->cls == float_class_normal) {
+    if (is_anynorm(a->cls)) {
         frac_truncjam(a, b);
     } else if (is_nan(a->cls)) {
         /* Discard the low bits of the NaN. */
@@ -XXX,XX +XXX,XX @@ static Int128 float128_to_int128_scalbn(float128 a, FloatRoundMode rmode,
         return int128_zero();
 
     case float_class_normal:
+    case float_class_denormal:
         if (parts_round_to_int_normal(&p, rmode, scale, 128 - 2)) {
             flags = float_flag_inexact;
         }
@@ -XXX,XX +XXX,XX @@ static Int128 float128_to_uint128_scalbn(float128 a, FloatRoundMode rmode,
         return int128_zero();
 
     case float_class_normal:
+    case float_class_denormal:
         if (parts_round_to_int_normal(&p, rmode, scale, 128 - 2)) {
             flags = float_flag_inexact;
             if (p.cls == float_class_zero) {
@@ -XXX,XX +XXX,XX @@ float32 float32_exp2(float32 a, float_status *status)
     float32_unpack_canonical(&xp, a, status);
     if (unlikely(xp.cls != float_class_normal)) {
         switch (xp.cls) {
+        case float_class_denormal:
+            break;
         case float_class_snan:
         case float_class_qnan:
             parts_return_nan(&xp, status);
@@ -XXX,XX +XXX,XX @@ float32 float32_exp2(float32 a, float_status *status)
         case float_class_zero:
             return float32_one;
         default:
-            break;
+            g_assert_not_reached();
         }
-        g_assert_not_reached();
     }
 
     float_raise(float_flag_inexact, status);
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index XXXXXXX..XXXXXXX 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -XXX,XX +XXX,XX @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
             frac_clear(p);
         } else {
             int shift = frac_normalize(p);
-            p->cls = float_class_normal;
+            p->cls = float_class_denormal;
             p->exp = fmt->frac_shift - fmt->exp_bias
                    - shift + !fmt->m68k_denormal;
         }
@@ -XXX,XX +XXX,XX @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
 static void partsN(uncanon)(FloatPartsN *p, float_status *s,
                             const FloatFmt *fmt)
 {
-    if (likely(p->cls == float_class_normal)) {
+    if (likely(is_anynorm(p->cls))) {
         parts_uncanon_normal(p, s, fmt);
     } else {
         switch (p->cls) {
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b,
 
     if (a->sign != b_sign) {
         /* Subtraction */
-        if (likely(ab_mask == float_cmask_normal)) {
+        if (likely(cmask_is_only_normals(ab_mask))) {
             if (parts_sub_normal(a, b)) {
                 return a;
             }
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b,
         }
     } else {
         /* Addition */
-        if (likely(ab_mask == float_cmask_normal)) {
+        if (likely(cmask_is_only_normals(ab_mask))) {
             parts_add_normal(a, b);
             return a;
         }
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b,
     }
 
     if (b->cls == float_class_zero) {
-        g_assert(a->cls == float_class_normal);
+        g_assert(is_anynorm(a->cls));
         return a;
     }
 
     g_assert(a->cls == float_class_zero);
-    g_assert(b->cls == float_class_normal);
+    g_assert(is_anynorm(b->cls));
  return_b:
     b->sign = b_sign;
     return b;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(mul)(FloatPartsN *a, FloatPartsN *b,
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
     bool sign = a->sign ^ b->sign;
 
-    if (likely(ab_mask == float_cmask_normal)) {
+    if (likely(cmask_is_only_normals(ab_mask))) {
         FloatPartsW tmp;
 
         frac_mulw(&tmp, a, b);
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(muladd_scalbn)(FloatPartsN *a, FloatPartsN *b,
         a->sign ^= 1;
     }
 
-    if (unlikely(ab_mask != float_cmask_normal)) {
+    if (unlikely(!cmask_is_only_normals(ab_mask))) {
         if (unlikely(ab_mask == float_cmask_infzero)) {
             float_raise(float_flag_invalid | float_flag_invalid_imz, s);
             goto d_nan;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(muladd_scalbn)(FloatPartsN *a, FloatPartsN *b,
         }
 
         g_assert(ab_mask & float_cmask_zero);
-        if (c->cls == float_class_normal) {
+        if (is_anynorm(c->cls)) {
             *a = *c;
             goto return_normal;
         }
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
     bool sign = a->sign ^ b->sign;
 
-    if (likely(ab_mask == float_cmask_normal)) {
+    if (likely(cmask_is_only_normals(ab_mask))) {
         a->sign = sign;
         a->exp -= b->exp + frac_div(a, b);
         return a;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(modrem)(FloatPartsN *a, FloatPartsN *b,
 {
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
 
-    if (likely(ab_mask == float_cmask_normal)) {
+    if (likely(cmask_is_only_normals(ab_mask))) {
         frac_modrem(a, b, mod_quot);
         return a;
     }
@@ -XXX,XX +XXX,XX @@ static void partsN(sqrt)(FloatPartsN *a, float_status *status,
 
     if (unlikely(a->cls != float_class_normal)) {
         switch (a->cls) {
+        case float_class_denormal:
+            break;
         case float_class_snan:
         case float_class_qnan:
             parts_return_nan(a, status);
@@ -XXX,XX +XXX,XX @@ static void partsN(round_to_int)(FloatPartsN *a, FloatRoundMode rmode,
     case float_class_inf:
         break;
     case float_class_normal:
+    case float_class_denormal:
         if (parts_round_to_int_normal(a, rmode, scale, fmt->frac_size)) {
             float_raise(float_flag_inexact, s);
         }
@@ -XXX,XX +XXX,XX @@ static int64_t partsN(float_to_sint)(FloatPartsN *p, FloatRoundMode rmode,
         return 0;
 
     case float_class_normal:
+    case float_class_denormal:
         /* TODO: N - 2 is frac_size for rounding; could use input fmt. */
         if (parts_round_to_int_normal(p, rmode, scale, N - 2)) {
             flags = float_flag_inexact;
@@ -XXX,XX +XXX,XX @@ static uint64_t partsN(float_to_uint)(FloatPartsN *p, FloatRoundMode rmode,
         return 0;
 
     case float_class_normal:
+    case float_class_denormal:
         /* TODO: N - 2 is frac_size for rounding; could use input fmt. */
         if (parts_round_to_int_normal(p, rmode, scale, N - 2)) {
             flags = float_flag_inexact;
@@ -XXX,XX +XXX,XX @@ static int64_t partsN(float_to_sint_modulo)(FloatPartsN *p,
         return 0;
 
     case float_class_normal:
+    case float_class_denormal:
         /* TODO: N - 2 is frac_size for rounding; could use input fmt. */
         if (parts_round_to_int_normal(p, rmode, 0, N - 2)) {
             flags = float_flag_inexact;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
     a_exp = a->exp;
     b_exp = b->exp;
 
-    if (unlikely(ab_mask != float_cmask_normal)) {
+    if (unlikely(!cmask_is_only_normals(ab_mask))) {
         switch (a->cls) {
         case float_class_normal:
+        case float_class_denormal:
             break;
         case float_class_inf:
             a_exp = INT16_MAX;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
         }
         switch (b->cls) {
         case float_class_normal:
+        case float_class_denormal:
             break;
         case float_class_inf:
             b_exp = INT16_MAX;
@@ -XXX,XX +XXX,XX @@ static FloatRelation partsN(compare)(FloatPartsN *a, FloatPartsN *b,
 {
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
 
-    if (likely(ab_mask == float_cmask_normal)) {
+    if (likely(cmask_is_only_normals(ab_mask))) {
         FloatRelation cmp;
 
         if (a->sign != b->sign) {
@@ -XXX,XX +XXX,XX @@ static void partsN(scalbn)(FloatPartsN *a, int n, float_status *s)
     case float_class_inf:
         break;
     case float_class_normal:
+    case float_class_denormal:
         a->exp += MIN(MAX(n, -0x10000), 0x10000);
         break;
     default:
@@ -XXX,XX +XXX,XX @@ static void partsN(log2)(FloatPartsN *a, float_status *s, const FloatFmt *fmt)
 
     if (unlikely(a->cls != float_class_normal)) {
         switch (a->cls) {
+        case float_class_denormal:
+            break;
         case float_class_snan:
         case float_class_qnan:
             parts_return_nan(a, s);
@@ -XXX,XX +XXX,XX @@ static void partsN(log2)(FloatPartsN *a, float_status *s, const FloatFmt *fmt)
             }
             return;
         default:
-            break;
+            g_assert_not_reached();
         }
-        g_assert_not_reached();
     }
     if (unlikely(a->sign)) {
         goto d_nan;
-- 
2.34.1

For the x86 and the Arm FEAT_AFP semantics, we need to be able to
tell the target code that the FPU operation has used an input
denormal.  Implement this; when it happens we set the new
float_flag_denormal_input_used.

Note that we only set this when an input denormal is actually used by
the operation: if the operation results in Invalid Operation or
Divide By Zero or the result is a NaN because some other input was a
NaN then we never needed to look at the input denormal and do not set
denormal_input_used.

We mostly do not need to adjust the hardfloat codepaths to deal with
this flag, because almost all hardfloat operations are already gated
on the input not being a denormal, and will fall back to softfloat
for a denormal input.  The only exception is the comparison
operations, where we need to add the check for input denormals, which
must now fall back to softfloat where they did not before.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/fpu/softfloat-types.h |  7 ++++
 fpu/softfloat.c               | 38 +++++++++++++++++---
 fpu/softfloat-parts.c.inc     | 68 ++++++++++++++++++++++++++++++++++-
 3 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index XXXXXXX..XXXXXXX 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -XXX,XX +XXX,XX @@ enum {
     float_flag_invalid_sqrt    = 0x0800,  /* sqrt(-x) */
     float_flag_invalid_cvti    = 0x1000,  /* non-nan to integer */
     float_flag_invalid_snan    = 0x2000,  /* any operand was snan */
+    /*
+     * An input was denormal and we used it (without flushing it to zero).
+     * Not set if we do not actually use the denormal input (e.g.
+     * because some other input was a NaN, or because the operation
+     * wasn't actually carried out (divide-by-zero; invalid))
+     */
+    float_flag_input_denormal_used = 0x4000,
 };
 
 /*
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index XXXXXXX..XXXXXXX 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -XXX,XX +XXX,XX @@ static void parts_float_to_ahp(FloatParts64 *a, float_status *s)
                                   float16_params_ahp.frac_size + 1);
         break;
 
-    case float_class_normal:
     case float_class_denormal:
+        float_raise(float_flag_input_denormal_used, s);
+        break;
+    case float_class_normal:
     case float_class_zero:
         break;
 
@@ -XXX,XX +XXX,XX @@ static void parts64_float_to_float(FloatParts64 *a, float_status *s)
     if (is_nan(a->cls)) {
         parts_return_nan(a, s);
     }
+    if (a->cls == float_class_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
 }
 
 static void parts128_float_to_float(FloatParts128 *a, float_status *s)
@@ -XXX,XX +XXX,XX @@ static void parts128_float_to_float(FloatParts128 *a, float_status *s)
     if (is_nan(a->cls)) {
         parts_return_nan(a, s);
     }
+    if (a->cls == float_class_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
 }
 
 #define parts_float_to_float(P, S) \
@@ -XXX,XX +XXX,XX @@ static void parts_float_to_float_narrow(FloatParts64 *a, FloatParts128 *b,
     a->sign = b->sign;
     a->exp = b->exp;
 
-    if (is_anynorm(a->cls)) {
+    switch (a->cls) {
+    case float_class_denormal:
+        float_raise(float_flag_input_denormal_used, s);
+        /* fall through */
+    case float_class_normal:
         frac_truncjam(a, b);
-    } else if (is_nan(a->cls)) {
+        break;
+    case float_class_snan:
+    case float_class_qnan:
         /* Discard the low bits of the NaN. */
         a->frac = b->frac_hi;
         parts_return_nan(a, s);
+        break;
+    default:
+        break;
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static void parts_float_to_float_widen(FloatParts128 *a, FloatParts64 *b,
     if (is_nan(a->cls)) {
         parts_return_nan(a, s);
     }
+    if (a->cls == float_class_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
 }
 
 float32 float16_to_float32(float16 a, bool ieee, float_status *s)
@@ -XXX,XX +XXX,XX @@ float32_hs_compare(float32 xa, float32 xb, float_status *s, bool is_quiet)
         goto soft;
     }
 
-    float32_input_flush2(&ua.s, &ub.s, s);
+    if (unlikely(float32_is_denormal(ua.s) || float32_is_denormal(ub.s))) {
+        /* We may need to set the input_denormal_used flag */
+        goto soft;
+    }
+
     if (isgreaterequal(ua.h, ub.h)) {
         if (isgreater(ua.h, ub.h)) {
             return float_relation_greater;
@@ -XXX,XX +XXX,XX @@ float64_hs_compare(float64 xa, float64 xb, float_status *s, bool is_quiet)
         goto soft;
     }
 
-    float64_input_flush2(&ua.s, &ub.s, s);
+    if (unlikely(float64_is_denormal(ua.s) || float64_is_denormal(ub.s))) {
+        /* We may need to set the input_denormal_used flag */
+        goto soft;
+    }
+
     if (isgreaterequal(ua.h, ub.h)) {
         if (isgreater(ua.h, ub.h)) {
             return float_relation_greater;
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index XXXXXXX..XXXXXXX 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(addsub)(FloatPartsN *a, FloatPartsN *b,
     bool b_sign = b->sign ^ subtract;
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
 
+    /*
+     * For addition and subtraction, we will consume an
+     * input denormal unless the other input is a NaN.
+     */
+    if ((ab_mask & (float_cmask_denormal | float_cmask_anynan)) ==
+        float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     if (a->sign != b_sign) {
         /* Subtraction */
         if (likely(cmask_is_only_normals(ab_mask))) {
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(mul)(FloatPartsN *a, FloatPartsN *b,
     if (likely(cmask_is_only_normals(ab_mask))) {
         FloatPartsW tmp;
 
+        if (ab_mask & float_cmask_denormal) {
+            float_raise(float_flag_input_denormal_used, s);
+        }
+
         frac_mulw(&tmp, a, b);
         frac_truncjam(a, &tmp);
 
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(mul)(FloatPartsN *a, FloatPartsN *b,
     }
 
     /* Multiply by 0 or Inf */
+    if (ab_mask & float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     if (ab_mask & float_cmask_inf) {
         a->cls = float_class_inf;
         a->sign = sign;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(muladd_scalbn)(FloatPartsN *a, FloatPartsN *b,
     if (flags & float_muladd_negate_result) {
         a->sign ^= 1;
     }
+
+    /*
+     * All result types except for "return the default NaN
+     * because this is an Invalid Operation" go through here;
+     * this matches the set of cases where we consumed a
+     * denormal input.
+     */
+    if (abc_mask & float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
     return a;
 
  return_sub_zero:
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
     bool sign = a->sign ^ b->sign;
 
     if (likely(cmask_is_only_normals(ab_mask))) {
+        if (ab_mask & float_cmask_denormal) {
+            float_raise(float_flag_input_denormal_used, s);
+        }
         a->sign = sign;
         a->exp -= b->exp + frac_div(a, b);
         return a;
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
         return parts_pick_nan(a, b, s);
     }
 
+    if ((ab_mask & float_cmask_denormal) && b->cls != float_class_zero) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     a->sign = sign;
 
     /* Inf / X */
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(modrem)(FloatPartsN *a, FloatPartsN *b,
     int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
 
     if (likely(cmask_is_only_normals(ab_mask))) {
+        if (ab_mask & float_cmask_denormal) {
+            float_raise(float_flag_input_denormal_used, s);
+        }
         frac_modrem(a, b, mod_quot);
         return a;
     }
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(modrem)(FloatPartsN *a, FloatPartsN *b,
         return a;
     }
 
+    if (ab_mask & float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     /* N % Inf; 0 % N */
     g_assert(b->cls == float_class_inf || a->cls == float_class_zero);
     return a;
@@ -XXX,XX +XXX,XX @@ static void partsN(sqrt)(FloatPartsN *a, float_status *status,
     if (unlikely(a->cls != float_class_normal)) {
         switch (a->cls) {
         case float_class_denormal:
+            if (!a->sign) {
+                /* -ve denormal will be InvalidOperation */
+                float_raise(float_flag_input_denormal_used, status);
+            }
             break;
         case float_class_snan:
         case float_class_qnan:
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
         if ((flags & (minmax_isnum | minmax_isnumber))
             && !(ab_mask & float_cmask_snan)
             && (ab_mask & ~float_cmask_qnan)) {
+            if (ab_mask & float_cmask_denormal) {
+                float_raise(float_flag_input_denormal_used, s);
+            }
             return is_nan(a->cls) ? b : a;
         }
 
@@ -XXX,XX +XXX,XX @@ static FloatPartsN *partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
         return parts_pick_nan(a, b, s);
     }
 
+    if (ab_mask & float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     a_exp = a->exp;
     b_exp = b->exp;
 
@@ -XXX,XX +XXX,XX @@ static FloatRelation partsN(compare)(FloatPartsN *a, FloatPartsN *b,
     if (likely(cmask_is_only_normals(ab_mask))) {
         FloatRelation cmp;
 
+        if (ab_mask & float_cmask_denormal) {
+            float_raise(float_flag_input_denormal_used, s);
+        }
+
         if (a->sign != b->sign) {
             goto a_sign;
         }
@@ -XXX,XX +XXX,XX @@ static FloatRelation partsN(compare)(FloatPartsN *a, FloatPartsN *b,
         return float_relation_unordered;
     }
 
+    if (ab_mask & float_cmask_denormal) {
+        float_raise(float_flag_input_denormal_used, s);
+    }
+
     if (ab_mask & float_cmask_zero) {
         if (ab_mask == float_cmask_zero) {
             return float_relation_equal;
@@ -XXX,XX +XXX,XX @@ static void partsN(scalbn)(FloatPartsN *a, int n, float_status *s)
     case float_class_zero:
     case float_class_inf:
         break;
-    case float_class_normal:
     case float_class_denormal:
+        float_raise(float_flag_input_denormal_used, s);
+        /* fall through */
+    case float_class_normal:
         a->exp += MIN(MAX(n, -0x10000), 0x10000);
         break;
     default:
@@ -XXX,XX +XXX,XX @@ static void partsN(log2)(FloatPartsN *a, float_status *s, const FloatFmt *fmt)
     if (unlikely(a->cls != float_class_normal)) {
         switch (a->cls) {
         case float_class_denormal:
+            if (!a->sign) {
+                /* -ve denormal will be InvalidOperation */
+                float_raise(float_flag_input_denormal_used, s);
+            }
             break;
         case float_class_snan:
         case float_class_qnan:
-- 
2.34.1

Currently we handle flushing of output denormals in uncanon_normal
always before we deal with rounding.  This works for architectures
that detect tininess before rounding, but is usually not the right
place when the architecture detects tininess after rounding.  For
example, for x86 the SDM states that the MXCSR FTZ control bit causes
outputs to be flushed to zero "when it detects a floating-point
underflow condition".  This means that we mustn't flush to zero if
the input is such that after rounding it is no longer tiny.

At least one of our guest architectures does underflow detection
after rounding but flushing of denormals before rounding (MIPS MSA);
this means we need to have a config knob for this that is separate
from our existing tininess_before_rounding setting.

Add an ftz_detection flag.  For consistency with
tininess_before_rounding, we make it default to "detect ftz after
rounding"; this means that we need to explicitly set the flag to
"detect ftz before rounding" on every existing architecture that sets
flush_to_zero, so that this commit has no behaviour change.
(This means more code change here but for the long term a less
confusing API.)

For several architectures the current behaviour is either
definitely or possibly wrong; annotate those with TODO comments.
These architectures are definitely wrong (and should detect
ftz after rounding):
 * x86
 * Alpha

For these architectures the spec is unclear:
 * MIPS (for non-MSA)
 * RX
 * SH4

PA-RISC makes ftz detection IMPDEF, but we aren't setting the
"tininess before rounding" setting that we ought to.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/fpu/softfloat-helpers.h | 11 +++++++++++
 include/fpu/softfloat-types.h   | 18 ++++++++++++++++++
 target/mips/fpu_helper.h        |  6 ++++++
 target/alpha/cpu.c              |  7 +++++++
 target/arm/cpu.c                |  1 +
 target/hppa/fpu_helper.c        | 11 +++++++++++
 target/i386/tcg/fpu_helper.c    |  8 ++++++++
 target/mips/msa.c               |  9 +++++++++
 target/ppc/cpu_init.c           |  3 +++
 target/rx/cpu.c                 |  8 ++++++++
 target/sh4/cpu.c                |  8 ++++++++
 target/tricore/helper.c         |  1 +
 tests/fp/fp-bench.c             |  1 +
 fpu/softfloat-parts.c.inc       | 21 +++++++++++++++------
 14 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/include/fpu/softfloat-helpers.h b/include/fpu/softfloat-helpers.h
index XXXXXXX..XXXXXXX 100644
--- a/include/fpu/softfloat-helpers.h
+++ b/include/fpu/softfloat-helpers.h
@@ -XXX,XX +XXX,XX @@ static inline void set_flush_inputs_to_zero(bool val, float_status *status)
     status->flush_inputs_to_zero = val;
 }
 
+static inline void set_float_ftz_detection(FloatFTZDetection d,
+                                           float_status *status)
+{
+    status->ftz_detection = d;
+}
+
 static inline void set_default_nan_mode(bool val, float_status *status)
 {
     status->default_nan_mode = val;
@@ -XXX,XX +XXX,XX @@ static inline bool get_default_nan_mode(const float_status *status)
     return status->default_nan_mode;
 }
 
+static inline FloatFTZDetection get_float_ftz_detection(const float_status *status)
+{
+    return status->ftz_detection;
+}
+
 #endif /* SOFTFLOAT_HELPERS_H */
diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index XXXXXXX..XXXXXXX 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -XXX,XX +XXX,XX @@ typedef enum __attribute__((__packed__)) {
     float_infzeronan_suppress_invalid = (1 << 7),
 } FloatInfZeroNaNRule;
 
+/*
+ * When flush_to_zero is set, should we detect denormal results to
+ * be flushed before or after rounding? For most architectures this
+ * should be set to match the tininess_before_rounding setting,
+ * but a few architectures, e.g. MIPS MSA, detect FTZ before
+ * rounding but tininess after rounding.
+ *
+ * This enum is arranged so that the default if the target doesn't
+ * configure it matches the default for tininess_before_rounding
+ * (i.e. "after rounding").
+ */
+typedef enum __attribute__((__packed__)) {
+    float_ftz_after_rounding = 0,
+    float_ftz_before_rounding = 1,
+} FloatFTZDetection;
+
 /*
  * Floating Point Status. Individual architectures may maintain
  * several versions of float_status for different functions. The
@@ -XXX,XX +XXX,XX @@ typedef struct float_status {
     bool tininess_before_rounding;
     /* should denormalised results go to zero and set output_denormal_flushed? */
     bool flush_to_zero;
+    /* do we detect and flush denormal results before or after rounding? */
+    FloatFTZDetection ftz_detection;
     /* should denormalised inputs go to zero and set input_denormal_flushed? */
     bool flush_inputs_to_zero;
     bool default_nan_mode;
diff --git a/target/mips/fpu_helper.h b/target/mips/fpu_helper.h
index XXXXXXX..XXXXXXX 100644
--- a/target/mips/fpu_helper.h
+++ b/target/mips/fpu_helper.h
@@ -XXX,XX +XXX,XX @@ static inline void fp_reset(CPUMIPSState *env)
      */
     set_float_2nan_prop_rule(float_2nan_prop_s_ab,
                              &env->active_fpu.fp_status);
+    /*
+     * TODO: the spec does't say clearly whether FTZ happens before
+     * or after rounding for normal FPU operations.
+     */
+    set_float_ftz_detection(float_ftz_before_rounding,
+                            &env->active_fpu.fp_status);
 }
 
 /* MSA */
diff --git a/target/alpha/cpu.c b/target/alpha/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/alpha/cpu.c
+++ b/target/alpha/cpu.c
@@ -XXX,XX +XXX,XX @@ static void alpha_cpu_initfn(Object *obj)
     set_float_2nan_prop_rule(float_2nan_prop_x87, &env->fp_status);
     /* Default NaN: sign bit clear, msb frac bit set */
     set_float_default_nan_pattern(0b01000000, &env->fp_status);
+    /*
+     * TODO: this is incorrect. The Alpha Architecture Handbook version 4
+     * section 4.7.7.11 says that we flush to zero for underflow cases, so
+     * this should be float_ftz_after_rounding to match the
+     * tininess_after_rounding (which is specified in section 4.7.5).
+     */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
 #if defined(CONFIG_USER_ONLY)
     env->flags = ENV_FLAG_PS_USER | ENV_FLAG_FEN;
     cpu_alpha_store_fpcr(env, (uint64_t)(FPCR_INVD | FPCR_DZED | FPCR_OVFD
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ void arm_register_el_change_hook(ARMCPU *cpu, ARMELChangeHookFn *hook,
 static void arm_set_default_fp_behaviours(float_status *s)
 {
     set_float_detect_tininess(float_tininess_before_rounding, s);
+    set_float_ftz_detection(float_ftz_before_rounding, s);
     set_float_2nan_prop_rule(float_2nan_prop_s_ab, s);
     set_float_3nan_prop_rule(float_3nan_prop_s_cab, s);
     set_float_infzeronan_rule(float_infzeronan_dnan_if_qnan, s);
diff --git a/target/hppa/fpu_helper.c b/target/hppa/fpu_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/hppa/fpu_helper.c
+++ b/target/hppa/fpu_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(loaded_fr0)(CPUHPPAState *env)
     set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->fp_status);
     /* Default NaN: sign bit clear, msb-1 frac bit set */
     set_float_default_nan_pattern(0b00100000, &env->fp_status);
+    /*
+     * "PA-RISC 2.0 Architecture" says it is IMPDEF whether the flushing
+     * enabled by FPSR.D happens before or after rounding. We pick "before"
+     * for consistency with tininess detection.
+     */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
+    /*
+     * TODO: "PA-RISC 2.0 Architecture" chapter 10 says that we should
+     * detect tininess before rounding, but we don't set that here so we
+     * get the default tininess after rounding.
+     */
 }
 
 void cpu_hppa_loaded_fr0(CPUHPPAState *env)
diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/i386/tcg/fpu_helper.c
+++ b/target/i386/tcg/fpu_helper.c
@@ -XXX,XX +XXX,XX @@ void cpu_init_fp_statuses(CPUX86State *env)
     set_float_default_nan_pattern(0b11000000, &env->fp_status);
     set_float_default_nan_pattern(0b11000000, &env->mmx_status);
     set_float_default_nan_pattern(0b11000000, &env->sse_status);
+    /*
+     * TODO: x86 does flush-to-zero detection after rounding (the SDM
+     * section 10.2.3.3 on the FTZ bit of MXCSR says that we flush
+     * when we detect underflow, which x86 does after rounding).
+     */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
+    set_float_ftz_detection(float_ftz_before_rounding, &env->mmx_status);
+    set_float_ftz_detection(float_ftz_before_rounding, &env->sse_status);
 }
 
 static inline uint8_t save_exception_flags(CPUX86State *env)
diff --git a/target/mips/msa.c b/target/mips/msa.c
index XXXXXXX..XXXXXXX 100644
--- a/target/mips/msa.c
+++ b/target/mips/msa.c
@@ -XXX,XX +XXX,XX @@ void msa_reset(CPUMIPSState *env)
     /* tininess detected after rounding.*/
     set_float_detect_tininess(float_tininess_after_rounding,
                               &env->active_tc.msa_fp_status);
+    /*
+     * MSACSR.FS detects tiny results to flush to zero before rounding
+     * (per "MIPS Architecture for Programmers Volume IV-j: The MIPS64 SIMD
+     * Architecture Module, Revision 1.1" section 3.5.4), even though it
+     * detects tininess after rounding for underflow purposes (section 3.4.2
+     * table 3.3).
+     */
+    set_float_ftz_detection(float_ftz_before_rounding,
+                            &env->active_tc.msa_fp_status);
 
     /*
      * According to MIPS specifications, if one of the two operands is
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index XXXXXXX..XXXXXXX 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -XXX,XX +XXX,XX @@ static void ppc_cpu_reset_hold(Object *obj, ResetType type)
     /* tininess for underflow is detected before rounding */
     set_float_detect_tininess(float_tininess_before_rounding,
                               &env->fp_status);
+    /* Similarly for flush-to-zero */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
+
     /*
      * PowerPC propagation rules:
      *  1. A if it sNaN or qNaN
diff --git a/target/rx/cpu.c b/target/rx/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/rx/cpu.c
+++ b/target/rx/cpu.c
@@ -XXX,XX +XXX,XX @@ static void rx_cpu_reset_hold(Object *obj, ResetType type)
     set_float_2nan_prop_rule(float_2nan_prop_x87, &env->fp_status);
     /* Default NaN value: sign bit clear, set frac msb */
     set_float_default_nan_pattern(0b01000000, &env->fp_status);
+    /*
+     * TODO: "RX Family RXv1 Instruction Set Architecture" is not 100% clear
+     * on whether flush-to-zero should happen before or after rounding, but
+     * section 1.3.2 says that it happens when underflow is detected, and
+     * implies that underflow is detected after rounding. So this may not
+     * be the correct setting.
+     */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
 }
 
 static ObjectClass *rx_cpu_class_by_name(const char *cpu_model)
diff --git a/target/sh4/cpu.c b/target/sh4/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/sh4/cpu.c
+++ b/target/sh4/cpu.c
@@ -XXX,XX +XXX,XX @@ static void superh_cpu_reset_hold(Object *obj, ResetType type)
     set_default_nan_mode(1, &env->fp_status);
     /* sign bit clear, set all frac bits other than msb */
     set_float_default_nan_pattern(0b00111111, &env->fp_status);
+    /*
+     * TODO: "SH-4 CPU Core Architecture ADCS 7182230F" doesn't say whether
+     * it detects tininess before or after rounding. Section 6.4 is clear
+     * that flush-to-zero happens when the result underflows, though, so
+     * either this should be "detect ftz after rounding" or else we should
+     * be setting "detect tininess before rounding".
+     */
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
 }
 
 static void superh_cpu_disas_set_info(CPUState *cpu, disassemble_info *info)
diff --git a/target/tricore/helper.c b/target/tricore/helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/tricore/helper.c
+++ b/target/tricore/helper.c
@@ -XXX,XX +XXX,XX @@ void fpu_set_state(CPUTriCoreState *env)
     set_flush_inputs_to_zero(1, &env->fp_status);
     set_flush_to_zero(1, &env->fp_status);
     set_float_detect_tininess(float_tininess_before_rounding, &env->fp_status);
+    set_float_ftz_detection(float_ftz_before_rounding, &env->fp_status);
     set_default_nan_mode(1, &env->fp_status);
     /* Default NaN pattern: sign bit clear, frac msb set */
     set_float_default_nan_pattern(0b01000000, &env->fp_status);
diff --git a/tests/fp/fp-bench.c b/tests/fp/fp-bench.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/fp/fp-bench.c
+++ b/tests/fp/fp-bench.c
@@ -XXX,XX +XXX,XX @@ static void run_bench(void)
     set_float_3nan_prop_rule(float_3nan_prop_s_cab, &soft_status);
     set_float_infzeronan_rule(float_infzeronan_dnan_if_qnan, &soft_status);
     set_float_default_nan_pattern(0b01000000, &soft_status);
+    set_float_ftz_detection(float_ftz_before_rounding, &soft_status);
 
     f = bench_funcs[operation][precision];
     g_assert(f);
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index XXXXXXX..XXXXXXX 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -XXX,XX +XXX,XX @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
             p->frac_lo &= ~round_mask;
         }
         frac_shr(p, frac_shift);
-    } else if (s->flush_to_zero) {
+    } else if (s->flush_to_zero &&
+               s->ftz_detection == float_ftz_before_rounding) {
         flags |= float_flag_output_denormal_flushed;
         p->cls = float_class_zero;
         exp = 0;
@@ -XXX,XX +XXX,XX @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
         exp = (p->frac_hi & DECOMPOSED_IMPLICIT_BIT) && !fmt->m68k_denormal;
         frac_shr(p, frac_shift);
 
-        if (is_tiny && (flags & float_flag_inexact)) {
-            flags |= float_flag_underflow;
-        }
-        if (exp == 0 && frac_eqz(p)) {
-            p->cls = float_class_zero;
+        if (is_tiny) {
+            if (s->flush_to_zero) {
+                assert(s->ftz_detection == float_ftz_after_rounding);
+                flags |= float_flag_output_denormal_flushed;
+                p->cls = float_class_zero;
+                exp = 0;
+                frac_clear(p);
+            } else if (flags & float_flag_inexact) {
+                flags |= float_flag_underflow;
+            }
+            if (exp == 0 && frac_eqz(p)) {
+                p->cls = float_class_zero;
+            }
         }
     }
     p->exp = exp;
-- 
2.34.1

The Armv8.7 FEAT_AFP feature defines three new control bits in
the FPCR:
 * FPCR.AH: "alternate floating point mode"; this changes floating
   point behaviour in a variety of ways, including:
    - the sign of a default NaN is 1, not 0
    - if FPCR.FZ is also 1, denormals detected after rounding
      with an unbounded exponent has been applied are flushed to zero
    - FPCR.FZ does not cause denormalized inputs to be flushed to zero
    - miscellaneous other corner-case behaviour changes
 * FPCR.FIZ: flush denormalized numbers to zero on input for
   most instructions
 * FPCR.NEP: makes scalar SIMD operations merge the result with
   higher vector elements in one of the source registers, instead
   of zeroing the higher elements of the destination

This commit defines the new bits in the FPCR, and allows them to be
read or written when FEAT_AFP is implemented.  Actual behaviour
changes will be implemented in subsequent commits.

Note that these are the first FPCR bits which don't appear in the
AArch32 FPSCR view of the register, and which share bit positions
with FPSR bits.

Part of FEAT_AFP is the new control bit FPCR.FIZ.  This bit affects
flushing of single and double precision denormal inputs to zero for
AArch64 floating point instructions.  (For half-precision, the
existing FPCR.FZ16 control remains the only one.)

FPCR.FIZ differs from FPCR.FZ in that if we flush an input denormal
only because of FPCR.FIZ then we should *not* set the cumulative
exception bit FPSR.IDC.

FEAT_AFP also defines that in AArch64 the existing FPCR.FZ only
applies when FPCR.AH is 0.

We can implement this by setting the "flush inputs to zero" state
appropriately when FPCR is written, and by not reflecting the
float_flag_input_denormal status flag into FPSR reads when it is the
result only of FPSR.FIZ.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/vfp_helper.c | 60 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 10 deletions(-)

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static inline uint32_t vfp_exceptbits_from_host(int host_bits)
 
 static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
 {
-    uint32_t i = 0;
+    uint32_t a32_flags = 0, a64_flags = 0;
 
-    i |= get_float_exception_flags(&env->vfp.fp_status_a32);
-    i |= get_float_exception_flags(&env->vfp.fp_status_a64);
-    i |= get_float_exception_flags(&env->vfp.standard_fp_status);
+    a32_flags |= get_float_exception_flags(&env->vfp.fp_status_a32);
+    a32_flags |= get_float_exception_flags(&env->vfp.standard_fp_status);
     /* FZ16 does not generate an input denormal exception.  */
-    i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32)
+    a32_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32)
           & ~float_flag_input_denormal_flushed);
-    i |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
+    a32_flags |= (get_float_exception_flags(&env->vfp.standard_fp_status_f16)
           & ~float_flag_input_denormal_flushed);
-    i |= (get_float_exception_flags(&env->vfp.standard_fp_status_f16)
+
+    a64_flags |= get_float_exception_flags(&env->vfp.fp_status_a64);
+    a64_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
           & ~float_flag_input_denormal_flushed);
-    return vfp_exceptbits_from_host(i);
+    /*
+     * Flushing an input denormal *only* because FPCR.FIZ == 1 does
+     * not set FPSR.IDC; if FPCR.FZ is also set then this takes
+     * precedence and IDC is set (see the FPUnpackBase pseudocode).
+     * So squash it unless (FPCR.AH == 0 && FPCR.FZ == 1).
+     * We only do this for the a64 flags because FIZ has no effect
+     * on AArch32 even if it is set.
+     */
+    if ((env->vfp.fpcr & (FPCR_FZ | FPCR_AH)) != FPCR_FZ) {
+        a64_flags &= ~float_flag_input_denormal_flushed;
+    }
+    return vfp_exceptbits_from_host(a32_flags | a64_flags);
 }
 
 static void vfp_clear_float_status_exc_flags(CPUARMState *env)
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.standard_fp_status_f16);
 }
 
+static void vfp_sync_and_clear_float_status_exc_flags(CPUARMState *env)
+{
+    /*
+     * Synchronize any pending exception-flag information in the
+     * float_status values into env->vfp.fpsr, and then clear out
+     * the float_status data.
+     */
+    env->vfp.fpsr |= vfp_get_fpsr_from_host(env);
+    vfp_clear_float_status_exc_flags(env);
+}
+
 static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
 {
     uint64_t changed = env->vfp.fpcr;
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
     if (changed & FPCR_FZ) {
         bool ftz_enabled = val & FPCR_FZ;
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_a32);
-        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a32);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_a64);
-        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a64);
+        /* FIZ is A64 only so FZ always makes A32 code flush inputs to zero */
+        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a32);
+    }
+    if (changed & (FPCR_FZ | FPCR_AH | FPCR_FIZ)) {
+        /*
+         * A64: Flush denormalized inputs to zero if FPCR.FIZ = 1, or
+         * both FPCR.AH = 0 and FPCR.FZ = 1.
+         */
+        bool fitz_enabled = (val & FPCR_FIZ) ||
+            (val & (FPCR_FZ | FPCR_AH)) == FPCR_FZ;
+        set_flush_inputs_to_zero(fitz_enabled, &env->vfp.fp_status_a64);
     }
     if (changed & FPCR_DN) {
         bool dnan_enabled = val & FPCR_DN;
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64);
     }
+    /*
+     * If any bits changed that we look at in vfp_get_fpsr_from_host(),
+     * we must sync the float_status flags into vfp.fpsr now (under the
+     * old regime) before we update vfp.fpcr.
+     */
+    if (changed & (FPCR_FZ | FPCR_AH | FPCR_FIZ)) {
+        vfp_sync_and_clear_float_status_exc_flags(env);
+    }
 }
 
 #else
-- 
2.34.1

When FPCR.AH is set, various behaviours of AArch64 floating point
operations which are controlled by softfloat config settings change:
 * tininess and ftz detection before/after rounding
 * NaN propagation order
 * result of 0 * Inf + NaN
 * default NaN value

When the guest changes the value of the AH bit, switch these config
settings on the fp_status_a64 and fp_status_f16_a64 float_status
fields.

This requires us to make the arm_set_default_fp_behaviours() function
global, since we now need to call it from cpu.c and vfp_helper.c; we
move it to vfp_helper.c so it can be next to the new
arm_set_ah_fp_behaviours().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/internals.h  |  4 +++
 target/arm/cpu.c        | 23 ----------------
 target/arm/vfp_helper.c | 58 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 61 insertions(+), 24 deletions(-)

diff --git a/target/arm/internals.h b/target/arm/internals.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -XXX,XX +XXX,XX @@ uint64_t gt_virt_cnt_offset(CPUARMState *env);
  * all EL1" scope; this covers stage 1 and stage 2.
  */
 int alle1_tlbmask(CPUARMState *env);
+
+/* Set the float_status behaviour to match the Arm defaults */
+void arm_set_default_fp_behaviours(float_status *s);
+
 #endif
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ void arm_register_el_change_hook(ARMCPU *cpu, ARMELChangeHookFn *hook,
     QLIST_INSERT_HEAD(&cpu->el_change_hooks, entry, node);
 }
 
-/*
- * Set the float_status behaviour to match the Arm defaults:
- *  * tininess-before-rounding
- *  * 2-input NaN propagation prefers SNaN over QNaN, and then
- *    operand A over operand B (see FPProcessNaNs() pseudocode)
- *  * 3-input NaN propagation prefers SNaN over QNaN, and then
- *    operand C over A over B (see FPProcessNaNs3() pseudocode,
- *    but note that for QEMU muladd is a * b + c, whereas for
- *    the pseudocode function the arguments are in the order c, a, b.
- *  * 0 * Inf + NaN returns the default NaN if the input NaN is quiet,
- *    and the input NaN if it is signalling
- *  * Default NaN has sign bit clear, msb frac bit set
- */
-static void arm_set_default_fp_behaviours(float_status *s)
-{
-    set_float_detect_tininess(float_tininess_before_rounding, s);
-    set_float_ftz_detection(float_ftz_before_rounding, s);
-    set_float_2nan_prop_rule(float_2nan_prop_s_ab, s);
-    set_float_3nan_prop_rule(float_3nan_prop_s_cab, s);
-    set_float_infzeronan_rule(float_infzeronan_dnan_if_qnan, s);
-    set_float_default_nan_pattern(0b01000000, s);
-}
-
 static void cp_reg_reset(gpointer key, gpointer value, gpointer opaque)
 {
     /* Reset a single ARMCPRegInfo register */
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@
 #include "exec/helper-proto.h"
 #include "internals.h"
 #include "cpu-features.h"
+#include "fpu/softfloat.h"
 #ifdef CONFIG_TCG
 #include "qemu/log.h"
-#include "fpu/softfloat.h"
 #endif
 
 /* VFP support.  We follow the convention used for VFP instructions:
    Single precision routines have a "s" suffix, double precision a
    "d" suffix.  */
 
+/*
+ * Set the float_status behaviour to match the Arm defaults:
+ *  * tininess-before-rounding
+ *  * 2-input NaN propagation prefers SNaN over QNaN, and then
+ *    operand A over operand B (see FPProcessNaNs() pseudocode)
+ *  * 3-input NaN propagation prefers SNaN over QNaN, and then
+ *    operand C over A over B (see FPProcessNaNs3() pseudocode,
+ *    but note that for QEMU muladd is a * b + c, whereas for
+ *    the pseudocode function the arguments are in the order c, a, b.
+ *  * 0 * Inf + NaN returns the default NaN if the input NaN is quiet,
+ *    and the input NaN if it is signalling
+ *  * Default NaN has sign bit clear, msb frac bit set
+ */
+void arm_set_default_fp_behaviours(float_status *s)
+{
+    set_float_detect_tininess(float_tininess_before_rounding, s);
+    set_float_ftz_detection(float_ftz_before_rounding, s);
+    set_float_2nan_prop_rule(float_2nan_prop_s_ab, s);
+    set_float_3nan_prop_rule(float_3nan_prop_s_cab, s);
+    set_float_infzeronan_rule(float_infzeronan_dnan_if_qnan, s);
+    set_float_default_nan_pattern(0b01000000, s);
+}
+
+/*
+ * Set the float_status behaviour to match the FEAT_AFP
+ * FPCR.AH=1 requirements:
+ *  * tininess-after-rounding
+ *  * 2-input NaN propagation prefers the first NaN
+ *  * 3-input NaN propagation prefers a over b over c
+ *  * 0 * Inf + NaN always returns the input NaN and doesn't
+ *    set Invalid for a QNaN
+ *  * default NaN has sign bit set, msb frac bit set
+ */
+static void arm_set_ah_fp_behaviours(float_status *s)
+{
+    set_float_detect_tininess(float_tininess_after_rounding, s);
+    set_float_ftz_detection(float_ftz_after_rounding, s);
+    set_float_2nan_prop_rule(float_2nan_prop_ab, s);
+    set_float_3nan_prop_rule(float_3nan_prop_abc, s);
+    set_float_infzeronan_rule(float_infzeronan_dnan_never |
+                              float_infzeronan_suppress_invalid, s);
+    set_float_default_nan_pattern(0b11000000, s);
+}
+
 #ifdef CONFIG_TCG
 
 /* Convert host exception flags to vfp form.  */
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64);
     }
+    if (changed & FPCR_AH) {
+        bool ah_enabled = val & FPCR_AH;
+
+        if (ah_enabled) {
+            /* Change behaviours for A64 FP operations */
+            arm_set_ah_fp_behaviours(&env->vfp.fp_status_a64);
+            arm_set_ah_fp_behaviours(&env->vfp.fp_status_f16_a64);
+        } else {
+            arm_set_default_fp_behaviours(&env->vfp.fp_status_a64);
+            arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a64);
+        }
+    }
     /*
      * If any bits changed that we look at in vfp_get_fpsr_from_host(),
      * we must sync the float_status flags into vfp.fpsr now (under the
-- 
2.34.1

When FPCR.AH = 1, some of the cumulative exception flags in the FPSR
behave slightly differently for A64 operations:
 * IDC is set when a denormal input is used without flushing
 * IXC (Inexact) is set when an output denormal is flushed to zero

Update vfp_get_fpsr_from_host() to do this.

Note that because half-precision operations never set IDC, we now
need to add float_flag_input_denormal_used to the set we mask out of
fp_status_f16_a64.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/vfp_helper.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static void arm_set_ah_fp_behaviours(float_status *s)
 #ifdef CONFIG_TCG
 
 /* Convert host exception flags to vfp form.  */
-static inline uint32_t vfp_exceptbits_from_host(int host_bits)
+static inline uint32_t vfp_exceptbits_from_host(int host_bits, bool ah)
 {
     uint32_t target_bits = 0;
 
@@ -XXX,XX +XXX,XX @@ static inline uint32_t vfp_exceptbits_from_host(int host_bits)
     if (host_bits & float_flag_input_denormal_flushed) {
         target_bits |= FPSR_IDC;
     }
+    /*
+     * With FPCR.AH, IDC is set when an input denormal is used,
+     * and flushing an output denormal to zero sets both IXC and UFC.
+     */
+    if (ah && (host_bits & float_flag_input_denormal_used)) {
+        target_bits |= FPSR_IDC;
+    }
+    if (ah && (host_bits & float_flag_output_denormal_flushed)) {
+        target_bits |= FPSR_IXC;
+    }
     return target_bits;
 }
 
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
 
     a64_flags |= get_float_exception_flags(&env->vfp.fp_status_a64);
     a64_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
-          & ~float_flag_input_denormal_flushed);
+          & ~(float_flag_input_denormal_flushed | float_flag_input_denormal_used));
     /*
      * Flushing an input denormal *only* because FPCR.FIZ == 1 does
      * not set FPSR.IDC; if FPCR.FZ is also set then this takes
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     if ((env->vfp.fpcr & (FPCR_FZ | FPCR_AH)) != FPCR_FZ) {
         a64_flags &= ~float_flag_input_denormal_flushed;
     }
-    return vfp_exceptbits_from_host(a32_flags | a64_flags);
+    return vfp_exceptbits_from_host(a64_flags, env->vfp.fpcr & FPCR_AH) |
+        vfp_exceptbits_from_host(a32_flags, false);
 }
 
 static void vfp_clear_float_status_exc_flags(CPUARMState *env)
-- 
2.34.1

We are going to need to generate different code in some cases when
FPCR.AH is 1.  For example:
 * Floating point neg and abs must not flip the sign bit of NaNs
 * some insns (FRECPE, FRECPS, FRECPX, FRSQRTE, FRSQRTS, and various
   BFCVT and BFM bfloat16 ops) need to use a different float_status
   to the usual one

Encode FPCR.AH into the A64 tbflags, so we can refer to it at
translate time.

Because we now have a bit in FPCR that affects codegen, we can't mark
the AArch64 FPCR register as being SUPPRESS_TB_END any more; writes
to it will now end the TB and trigger a regeneration of hflags.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.h               | 1 +
 target/arm/tcg/translate.h     | 2 ++
 target/arm/helper.c            | 2 +-
 target/arm/tcg/hflags.c        | 4 ++++
 target/arm/tcg/translate-a64.c | 1 +
 5 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ FIELD(TBFLAG_A64, NV2, 34, 1)
 FIELD(TBFLAG_A64, NV2_MEM_E20, 35, 1)
 /* Set if FEAT_NV2 RAM accesses are big-endian */
 FIELD(TBFLAG_A64, NV2_MEM_BE, 36, 1)
+FIELD(TBFLAG_A64, AH, 37, 1)   /* FPCR.AH */
 
 /*
  * Helpers for using the above. Note that only the A64 accessors use
diff --git a/target/arm/tcg/translate.h b/target/arm/tcg/translate.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate.h
+++ b/target/arm/tcg/translate.h
@@ -XXX,XX +XXX,XX @@ typedef struct DisasContext {
     bool nv2_mem_e20;
     /* True if NV2 enabled and NV2 RAM accesses are big-endian */
     bool nv2_mem_be;
+    /* True if FPCR.AH is 1 (alternate floating point handling) */
+    bool fpcr_ah;
     /*
      * >= 0, a copy of PSTATE.BTYPE, which will be 0 without v8.5-BTI.
      *  < 0, set by the current instruction.
diff --git a/target/arm/helper.c b/target/arm/helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -XXX,XX +XXX,XX @@ static const ARMCPRegInfo v8_cp_reginfo[] = {
       .writefn = aa64_daif_write, .resetfn = arm_cp_reset_ignore },
     { .name = "FPCR", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 3, .opc2 = 0, .crn = 4, .crm = 4,
-      .access = PL0_RW, .type = ARM_CP_FPU | ARM_CP_SUPPRESS_TB_END,
+      .access = PL0_RW, .type = ARM_CP_FPU,
       .readfn = aa64_fpcr_read, .writefn = aa64_fpcr_write },
     { .name = "FPSR", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 3, .opc2 = 1, .crn = 4, .crm = 4,
diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/hflags.c
+++ b/target/arm/tcg/hflags.c
@@ -XXX,XX +XXX,XX @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
         DP_TBFLAG_A64(flags, TCMA, aa64_va_parameter_tcma(tcr, mmu_idx));
     }
 
+    if (env->vfp.fpcr & FPCR_AH) {
+        DP_TBFLAG_A64(flags, AH, 1);
+    }
+
     return rebuild_hflags_common(env, fp_el, mmu_idx, flags);
 }
 
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void aarch64_tr_init_disas_context(DisasContextBase *dcbase,
     dc->nv2 = EX_TBFLAG_A64(tb_flags, NV2);
     dc->nv2_mem_e20 = EX_TBFLAG_A64(tb_flags, NV2_MEM_E20);
     dc->nv2_mem_be = EX_TBFLAG_A64(tb_flags, NV2_MEM_BE);
+    dc->fpcr_ah = EX_TBFLAG_A64(tb_flags, AH);
     dc->vec_len = 0;
     dc->vec_stride = 0;
     dc->cp_regs = arm_cpu->cp_regs;
-- 
2.34.1

When FPCR.AH is 1, the behaviour of some instructions changes:
 * AdvSIMD BFCVT, BFCVTN, BFCVTN2, BFMLALB, BFMLALT
 * SVE BFCVT, BFCVTNT, BFMLALB, BFMLALT, BFMLSLB, BFMLSLT
 * SME BFCVT, BFCVTN, BFMLAL, BFMLSL (these are all in SME2 which
   QEMU does not yet implement)
 * FRECPE, FRECPS, FRECPX, FRSQRTE, FRSQRTS

The behaviour change is:
 * the instructions do not update the FPSR cumulative exception flags
 * trapped floating point exceptions are disabled (a no-op for QEMU,
   which doesn't implement FPCR.{IDE,IXE,UFE,OFE,DZE,IOE})
 * rounding is always round-to-nearest-even regardless of FPCR.RMode
 * denormalized inputs and outputs are always flushed to zero, as if
   FPCR.{FZ,FIZ} is {1,1}
 * FPCR.FZ16 is still honoured for half-precision inputs

(See the Arm ARM DDI0487L.a section A1.5.9.)

We can provide all these behaviours with another pair of float_status fields
which we use only for these insns, when FPCR.AH is 1. These float_status
fields will always have:
 * flush_to_zero and flush_inputs_to_zero set for the non-F16 field
 * rounding mode set to round-to-nearest-even
and so the only FPCR fields they need to honour are DN and FZ16.

In this commit we only define the new fp_status fields and give them
the required behaviour when FPSR is updated.  In subsequent commits
we will arrange to use this new fp_status field for the instructions
that should be affected by FPCR.AH in this way.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.h           | 15 +++++++++++++++
 target/arm/internals.h     |  2 ++
 target/arm/tcg/translate.h | 14 ++++++++++++++
 target/arm/cpu.c           |  4 ++++
 target/arm/vfp_helper.c    | 13 ++++++++++++-
 5 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
          *  standard_fp_status : the ARM "Standard FPSCR Value"
          *  standard_fp_status_fp16 : used for half-precision
          *       calculations with the ARM "Standard FPSCR Value"
+         *  ah_fp_status: used for the A64 insns which change behaviour
+         *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
+         *       and the reciprocal and square root estimate/step insns)
+         *  ah_fp_status_f16: used for the A64 insns which change behaviour
+         *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
+         *       and the reciprocal and square root estimate/step insns);
+         *       for half-precision
          *
          * Half-precision operations are governed by a separate
          * flush-to-zero control bit in FPSCR:FZ16. We pass a separate
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
          * the "standard FPSCR" tracks the FPSCR.FZ16 bit rather than
          * using a fixed value for it.
          *
+         * The ah_fp_status is needed because some insns have different
+         * behaviour when FPCR.AH == 1: they don't update cumulative
+         * exception flags, they act like FPCR.{FZ,FIZ} = {1,1} and
+         * they ignore FPCR.RMode. But they don't ignore FPCR.FZ16,
+         * which means we need an ah_fp_status_f16 as well.
+         *
          * To avoid having to transfer exception bits around, we simply
          * say that the FPSCR cumulative exception flags are the logical
          * OR of the flags in the four fp statuses. This relies on the
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
         float_status fp_status_f16_a64;
         float_status standard_fp_status;
         float_status standard_fp_status_f16;
+        float_status ah_fp_status;
+        float_status ah_fp_status_f16;
 
         uint64_t zcr_el[4];   /* ZCR_EL[1-3] */
         uint64_t smcr_el[4];  /* SMCR_EL[1-3] */
diff --git a/target/arm/internals.h b/target/arm/internals.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -XXX,XX +XXX,XX @@ int alle1_tlbmask(CPUARMState *env);
 
 /* Set the float_status behaviour to match the Arm defaults */
 void arm_set_default_fp_behaviours(float_status *s);
+/* Set the float_status behaviour to match Arm FPCR.AH=1 behaviour */
+void arm_set_ah_fp_behaviours(float_status *s);
 
 #endif
diff --git a/target/arm/tcg/translate.h b/target/arm/tcg/translate.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate.h
+++ b/target/arm/tcg/translate.h
@@ -XXX,XX +XXX,XX @@ typedef enum ARMFPStatusFlavour {
     FPST_A64,
     FPST_A32_F16,
     FPST_A64_F16,
+    FPST_AH,
+    FPST_AH_F16,
     FPST_STD,
     FPST_STD_F16,
 } ARMFPStatusFlavour;
@@ -XXX,XX +XXX,XX @@ typedef enum ARMFPStatusFlavour {
  *   for AArch32 operations controlled by the FPCR where FPCR.FZ16 is to be used
  * FPST_A64_F16
  *   for AArch64 operations controlled by the FPCR where FPCR.FZ16 is to be used
+ * FPST_AH:
+ *   for AArch64 operations which change behaviour when AH=1 (specifically,
+ *   bfloat16 conversions and multiplies, and the reciprocal and square root
+ *   estimate/step insns)
+ * FPST_AH_F16:
+ *   ditto, but for half-precision operations
  * FPST_STD
  *   for A32/T32 Neon operations using the "standard FPSCR value"
  * FPST_STD_F16
@@ -XXX,XX +XXX,XX @@ static inline TCGv_ptr fpstatus_ptr(ARMFPStatusFlavour flavour)
     case FPST_A64_F16:
         offset = offsetof(CPUARMState, vfp.fp_status_f16_a64);
         break;
+    case FPST_AH:
+        offset = offsetof(CPUARMState, vfp.ah_fp_status);
+        break;
+    case FPST_AH_F16:
+        offset = offsetof(CPUARMState, vfp.ah_fp_status_f16);
+        break;
     case FPST_STD:
         offset = offsetof(CPUARMState, vfp.standard_fp_status);
         break;
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a64);
     arm_set_default_fp_behaviours(&env->vfp.standard_fp_status_f16);
+    arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status);
+    set_flush_to_zero(1, &env->vfp.ah_fp_status);
+    set_flush_inputs_to_zero(1, &env->vfp.ah_fp_status);
+    arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status_f16);
 
 #ifndef CONFIG_USER_ONLY
     if (kvm_enabled()) {
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ void arm_set_default_fp_behaviours(float_status *s)
  *    set Invalid for a QNaN
  *  * default NaN has sign bit set, msb frac bit set
  */
-static void arm_set_ah_fp_behaviours(float_status *s)
+void arm_set_ah_fp_behaviours(float_status *s)
 {
     set_float_detect_tininess(float_tininess_after_rounding, s);
     set_float_ftz_detection(float_ftz_after_rounding, s);
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     a64_flags |= get_float_exception_flags(&env->vfp.fp_status_a64);
     a64_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
           & ~(float_flag_input_denormal_flushed | float_flag_input_denormal_used));
+    /*
+     * We do not merge in flags from ah_fp_status or ah_fp_status_f16, because
+     * they are used for insns that must not set the cumulative exception bits.
+     */
+
     /*
      * Flushing an input denormal *only* because FPCR.FIZ == 1 does
      * not set FPSR.IDC; if FPCR.FZ is also set then this takes
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a64);
     set_float_exception_flags(0, &env->vfp.standard_fp_status);
     set_float_exception_flags(0, &env->vfp.standard_fp_status_f16);
+    set_float_exception_flags(0, &env->vfp.ah_fp_status);
+    set_float_exception_flags(0, &env->vfp.ah_fp_status_f16);
 }
 
 static void vfp_sync_and_clear_float_status_exc_flags(CPUARMState *env)
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
         set_flush_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16);
+        set_flush_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16);
+        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
     }
     if (changed & FPCR_FZ) {
         bool ftz_enabled = val & FPCR_FZ;
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_a64);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64);
+        set_default_nan_mode(dnan_enabled, &env->vfp.ah_fp_status);
+        set_default_nan_mode(dnan_enabled, &env->vfp.ah_fp_status_f16);
     }
     if (changed & FPCR_AH) {
         bool ah_enabled = val & FPCR_AH;
-- 
2.34.1

For the instructions FRECPE, FRECPS, FRECPX, FRSQRTE, FRSQRTS, use
FPST_FPCR_AH or FPST_FPCR_AH_F16 when FPCR.AH is 1, so that they get
the required behaviour changes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.h |  13 ++++
 target/arm/tcg/translate-a64.c | 119 +++++++++++++++++++++++++--------
 target/arm/tcg/translate-sve.c |  30 ++++++---
 3 files changed, 127 insertions(+), 35 deletions(-)

diff --git a/target/arm/tcg/translate-a64.h b/target/arm/tcg/translate-a64.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.h
+++ b/target/arm/tcg/translate-a64.h
@@ -XXX,XX +XXX,XX @@ static inline TCGv_ptr pred_full_reg_ptr(DisasContext *s, int regno)
     return ret;
 }
 
+/*
+ * Return the ARMFPStatusFlavour to use based on element size and
+ * whether FPCR.AH is set.
+ */
+static inline ARMFPStatusFlavour select_ah_fpst(DisasContext *s, MemOp esz)
+{
+    if (s->fpcr_ah) {
+        return esz == MO_16 ? FPST_AH_F16 : FPST_AH;
+    } else {
+        return esz == MO_16 ? FPST_A64_F16 : FPST_A64;
+    }
+}
+
 bool disas_sve(DisasContext *, uint32_t);
 bool disas_sme(DisasContext *, uint32_t);
 
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void gen_gvec_op3_ool(DisasContext *s, bool is_q, int rd,
  * an out-of-line helper.
  */
 static void gen_gvec_op3_fpst(DisasContext *s, bool is_q, int rd, int rn,
-                              int rm, bool is_fp16, int data,
+                              int rm, ARMFPStatusFlavour fpsttype, int data,
                               gen_helper_gvec_3_ptr *fn)
 {
-    TCGv_ptr fpst = fpstatus_ptr(is_fp16 ? FPST_A64_F16 : FPST_A64);
+    TCGv_ptr fpst = fpstatus_ptr(fpsttype);
     tcg_gen_gvec_3_ptr(vec_full_reg_offset(s, rd),
                        vec_full_reg_offset(s, rn),
                        vec_full_reg_offset(s, rm), fpst,
@@ -XXX,XX +XXX,XX @@ typedef struct FPScalar {
     void (*gen_d)(TCGv_i64, TCGv_i64, TCGv_i64, TCGv_ptr);
 } FPScalar;
 
-static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
+static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
+                                        const FPScalar *f,
+                                        ARMFPStatusFlavour fpsttype)
 {
     switch (a->esz) {
     case MO_64:
         if (fp_access_check(s)) {
             TCGv_i64 t0 = read_fp_dreg(s, a->rn);
             TCGv_i64 t1 = read_fp_dreg(s, a->rm);
-            f->gen_d(t0, t0, t1, fpstatus_ptr(FPST_A64));
+            f->gen_d(t0, t0, t1, fpstatus_ptr(fpsttype));
             write_fp_dreg(s, a->rd, t0);
         }
         break;
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
         if (fp_access_check(s)) {
             TCGv_i32 t0 = read_fp_sreg(s, a->rn);
             TCGv_i32 t1 = read_fp_sreg(s, a->rm);
-            f->gen_s(t0, t0, t1, fpstatus_ptr(FPST_A64));
+            f->gen_s(t0, t0, t1, fpstatus_ptr(fpsttype));
             write_fp_sreg(s, a->rd, t0);
         }
         break;
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
         if (fp_access_check(s)) {
             TCGv_i32 t0 = read_fp_hreg(s, a->rn);
             TCGv_i32 t1 = read_fp_hreg(s, a->rm);
-            f->gen_h(t0, t0, t1, fpstatus_ptr(FPST_A64_F16));
+            f->gen_h(t0, t0, t1, fpstatus_ptr(fpsttype));
             write_fp_sreg(s, a->rd, t0);
         }
         break;
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
     return true;
 }
 
+static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
+{
+    return do_fp3_scalar_with_fpsttype(s, a, f,
+                                       a->esz == MO_16 ?
+                                       FPST_A64_F16 : FPST_A64);
+}
+
+static bool do_fp3_scalar_ah(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
+{
+    return do_fp3_scalar_with_fpsttype(s, a, f, select_ah_fpst(s, a->esz));
+}
+
 static const FPScalar f_scalar_fadd = {
     gen_helper_vfp_addh,
     gen_helper_vfp_adds,
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_frecps = {
     gen_helper_recpsf_f32,
     gen_helper_recpsf_f64,
 };
-TRANS(FRECPS_s, do_fp3_scalar, a, &f_scalar_frecps)
+TRANS(FRECPS_s, do_fp3_scalar_ah, a, &f_scalar_frecps)
 
 static const FPScalar f_scalar_frsqrts = {
     gen_helper_rsqrtsf_f16,
     gen_helper_rsqrtsf_f32,
     gen_helper_rsqrtsf_f64,
 };
-TRANS(FRSQRTS_s, do_fp3_scalar, a, &f_scalar_frsqrts)
+TRANS(FRSQRTS_s, do_fp3_scalar_ah, a, &f_scalar_frsqrts)
 
 static bool do_fcmp0_s(DisasContext *s, arg_rr_e *a,
                        const FPScalar *f, bool swap)
@@ -XXX,XX +XXX,XX @@ TRANS(CMHS_s, do_cmop_d, a, TCG_COND_GEU)
 TRANS(CMEQ_s, do_cmop_d, a, TCG_COND_EQ)
 TRANS(CMTST_s, do_cmop_d, a, TCG_COND_TSTNE)
 
-static bool do_fp3_vector(DisasContext *s, arg_qrrr_e *a, int data,
-                          gen_helper_gvec_3_ptr * const fns[3])
+static bool do_fp3_vector_with_fpsttype(DisasContext *s, arg_qrrr_e *a,
+                                        int data,
+                                        gen_helper_gvec_3_ptr * const fns[3],
+                                        ARMFPStatusFlavour fpsttype)
 {
     MemOp esz = a->esz;
     int check = fp_access_check_vector_hsd(s, a->q, esz);
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_vector(DisasContext *s, arg_qrrr_e *a, int data,
         return check == 0;
     }
 
-    gen_gvec_op3_fpst(s, a->q, a->rd, a->rn, a->rm,
-                      esz == MO_16, data, fns[esz - 1]);
+    gen_gvec_op3_fpst(s, a->q, a->rd, a->rn, a->rm, fpsttype,
+                      data, fns[esz - 1]);
     return true;
 }
 
+static bool do_fp3_vector(DisasContext *s, arg_qrrr_e *a, int data,
+                          gen_helper_gvec_3_ptr * const fns[3])
+{
+    return do_fp3_vector_with_fpsttype(s, a, data, fns,
+                                       a->esz == MO_16 ?
+                                       FPST_A64_F16 : FPST_A64);
+}
+
+static bool do_fp3_vector_ah(DisasContext *s, arg_qrrr_e *a, int data,
+                             gen_helper_gvec_3_ptr * const f[3])
+{
+    return do_fp3_vector_with_fpsttype(s, a, data, f,
+                                       select_ah_fpst(s, a->esz));
+}
+
 static gen_helper_gvec_3_ptr * const f_vector_fadd[3] = {
     gen_helper_gvec_fadd_h,
     gen_helper_gvec_fadd_s,
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_3_ptr * const f_vector_frecps[3] = {
     gen_helper_gvec_recps_s,
     gen_helper_gvec_recps_d,
 };
-TRANS(FRECPS_v, do_fp3_vector, a, 0, f_vector_frecps)
+TRANS(FRECPS_v, do_fp3_vector_ah, a, 0, f_vector_frecps)
 
 static gen_helper_gvec_3_ptr * const f_vector_frsqrts[3] = {
     gen_helper_gvec_rsqrts_h,
     gen_helper_gvec_rsqrts_s,
     gen_helper_gvec_rsqrts_d,
 };
-TRANS(FRSQRTS_v, do_fp3_vector, a, 0, f_vector_frsqrts)
+TRANS(FRSQRTS_v, do_fp3_vector_ah, a, 0, f_vector_frsqrts)
 
 static gen_helper_gvec_3_ptr * const f_vector_faddp[3] = {
     gen_helper_gvec_faddp_h,
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_vector_idx(DisasContext *s, arg_qrrx_e *a,
     }
 
     gen_gvec_op3_fpst(s, a->q, a->rd, a->rn, a->rm,
-                      esz == MO_16, a->idx, fns[esz - 1]);
+                      esz == MO_16 ? FPST_A64_F16 : FPST_A64,
+                      a->idx, fns[esz - 1]);
     return true;
 }
 
@@ -XXX,XX +XXX,XX @@ typedef struct FPScalar1 {
     void (*gen_d)(TCGv_i64, TCGv_i64, TCGv_ptr);
 } FPScalar1;
 
-static bool do_fp1_scalar(DisasContext *s, arg_rr_e *a,
-                          const FPScalar1 *f, int rmode)
+static bool do_fp1_scalar_with_fpsttype(DisasContext *s, arg_rr_e *a,
+                                        const FPScalar1 *f, int rmode,
+                                        ARMFPStatusFlavour fpsttype)
 {
     TCGv_i32 tcg_rmode = NULL;
     TCGv_ptr fpst;
@@ -XXX,XX +XXX,XX @@ static bool do_fp1_scalar(DisasContext *s, arg_rr_e *a,
         return check == 0;
     }
 
-    fpst = fpstatus_ptr(a->esz == MO_16 ? FPST_A64_F16 : FPST_A64);
+    fpst = fpstatus_ptr(fpsttype);
     if (rmode >= 0) {
         tcg_rmode = gen_set_rmode(rmode, fpst);
     }
@@ -XXX,XX +XXX,XX @@ static bool do_fp1_scalar(DisasContext *s, arg_rr_e *a,
     return true;
 }
 
+static bool do_fp1_scalar(DisasContext *s, arg_rr_e *a,
+                          const FPScalar1 *f, int rmode)
+{
+    return do_fp1_scalar_with_fpsttype(s, a, f, rmode,
+                                       a->esz == MO_16 ?
+                                       FPST_A64_F16 : FPST_A64);
+}
+
+static bool do_fp1_scalar_ah(DisasContext *s, arg_rr_e *a,
+                             const FPScalar1 *f, int rmode)
+{
+    return do_fp1_scalar_with_fpsttype(s, a, f, rmode, select_ah_fpst(s, a->esz));
+}
+
 static const FPScalar1 f_scalar_fsqrt = {
     gen_helper_vfp_sqrth,
     gen_helper_vfp_sqrts,
@@ -XXX,XX +XXX,XX @@ static const FPScalar1 f_scalar_frecpe = {
     gen_helper_recpe_f32,
     gen_helper_recpe_f64,
 };
-TRANS(FRECPE_s, do_fp1_scalar, a, &f_scalar_frecpe, -1)
+TRANS(FRECPE_s, do_fp1_scalar_ah, a, &f_scalar_frecpe, -1)
 
 static const FPScalar1 f_scalar_frecpx = {
     gen_helper_frecpx_f16,
     gen_helper_frecpx_f32,
     gen_helper_frecpx_f64,
 };
-TRANS(FRECPX_s, do_fp1_scalar, a, &f_scalar_frecpx, -1)
+TRANS(FRECPX_s, do_fp1_scalar_ah, a, &f_scalar_frecpx, -1)
 
 static const FPScalar1 f_scalar_frsqrte = {
     gen_helper_rsqrte_f16,
     gen_helper_rsqrte_f32,
     gen_helper_rsqrte_f64,
 };
-TRANS(FRSQRTE_s, do_fp1_scalar, a, &f_scalar_frsqrte, -1)
+TRANS(FRSQRTE_s, do_fp1_scalar_ah, a, &f_scalar_frsqrte, -1)
 
 static bool trans_FCVT_s_ds(DisasContext *s, arg_rr *a)
 {
@@ -XXX,XX +XXX,XX @@ TRANS_FEAT(FRINT64Z_v, aa64_frint, do_fp1_vector, a,
            &f_scalar_frint64, FPROUNDING_ZERO)
 TRANS_FEAT(FRINT64X_v, aa64_frint, do_fp1_vector, a, &f_scalar_frint64, -1)
 
-static bool do_gvec_op2_fpst(DisasContext *s, MemOp esz, bool is_q,
-                             int rd, int rn, int data,
-                             gen_helper_gvec_2_ptr * const fns[3])
+static bool do_gvec_op2_fpst_with_fpsttype(DisasContext *s, MemOp esz,
+                                           bool is_q, int rd, int rn, int data,
+                                           gen_helper_gvec_2_ptr * const fns[3],
+                                           ARMFPStatusFlavour fpsttype)
 {
     int check = fp_access_check_vector_hsd(s, is_q, esz);
     TCGv_ptr fpst;
@@ -XXX,XX +XXX,XX @@ static bool do_gvec_op2_fpst(DisasContext *s, MemOp esz, bool is_q,
         return check == 0;
     }
 
-    fpst = fpstatus_ptr(esz == MO_16 ? FPST_A64_F16 : FPST_A64);
+    fpst = fpstatus_ptr(fpsttype);
     tcg_gen_gvec_2_ptr(vec_full_reg_offset(s, rd),
                        vec_full_reg_offset(s, rn), fpst,
                        is_q ? 16 : 8, vec_full_reg_size(s),
@@ -XXX,XX +XXX,XX @@ static bool do_gvec_op2_fpst(DisasContext *s, MemOp esz, bool is_q,
     return true;
 }
 
+static bool do_gvec_op2_fpst(DisasContext *s, MemOp esz, bool is_q,
+                             int rd, int rn, int data,
+                             gen_helper_gvec_2_ptr * const fns[3])
+{
+    return do_gvec_op2_fpst_with_fpsttype(s, esz, is_q, rd, rn, data, fns,
+                                          esz == MO_16 ? FPST_A64_F16 :
+                                          FPST_A64);
+}
+
+static bool do_gvec_op2_ah_fpst(DisasContext *s, MemOp esz, bool is_q,
+                                int rd, int rn, int data,
+                                gen_helper_gvec_2_ptr * const fns[3])
+{
+    return do_gvec_op2_fpst_with_fpsttype(s, esz, is_q, rd, rn, data,
+                                          fns, select_ah_fpst(s, esz));
+}
+
 static gen_helper_gvec_2_ptr * const f_scvtf_v[] = {
     gen_helper_gvec_vcvt_sh,
     gen_helper_gvec_vcvt_sf,
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_2_ptr * const f_frecpe[] = {
     gen_helper_gvec_frecpe_s,
     gen_helper_gvec_frecpe_d,
 };
-TRANS(FRECPE_v, do_gvec_op2_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frecpe)
+TRANS(FRECPE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frecpe)
 
 static gen_helper_gvec_2_ptr * const f_frsqrte[] = {
     gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s,
     gen_helper_gvec_frsqrte_d,
 };
-TRANS(FRSQRTE_v, do_gvec_op2_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frsqrte)
+TRANS(FRSQRTE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frsqrte)
 
 static bool trans_FCVTL_v(DisasContext *s, arg_qrr_e *a)
 {
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ static bool gen_gvec_fpst_zz(DisasContext *s, gen_helper_gvec_2_ptr *fn,
     return true;
 }
 
-static bool gen_gvec_fpst_arg_zz(DisasContext *s, gen_helper_gvec_2_ptr *fn,
-                                 arg_rr_esz *a, int data)
+static bool gen_gvec_fpst_ah_arg_zz(DisasContext *s, gen_helper_gvec_2_ptr *fn,
+                                    arg_rr_esz *a, int data)
 {
     return gen_gvec_fpst_zz(s, fn, a->rd, a->rn, data,
-                            a->esz == MO_16 ? FPST_A64_F16 : FPST_A64);
+                            select_ah_fpst(s, a->esz));
 }
 
 /* Invoke an out-of-line helper on 3 Zregs. */
@@ -XXX,XX +XXX,XX @@ static bool gen_gvec_fpst_arg_zzz(DisasContext *s, gen_helper_gvec_3_ptr *fn,
                              a->esz == MO_16 ? FPST_A64_F16 : FPST_A64);
 }
 
+static bool gen_gvec_fpst_ah_arg_zzz(DisasContext *s, gen_helper_gvec_3_ptr *fn,
+                                     arg_rrr_esz *a, int data)
+{
+    return gen_gvec_fpst_zzz(s, fn, a->rd, a->rn, a->rm, data,
+                             select_ah_fpst(s, a->esz));
+}
+
 /* Invoke an out-of-line helper on 4 Zregs. */
 static bool gen_gvec_ool_zzzz(DisasContext *s, gen_helper_gvec_4 *fn,
                               int rd, int rn, int rm, int ra, int data)
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_2_ptr * const frecpe_fns[] = {
     NULL,                     gen_helper_gvec_frecpe_h,
     gen_helper_gvec_frecpe_s, gen_helper_gvec_frecpe_d,
 };
-TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_arg_zz, frecpe_fns[a->esz], a, 0)
+TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frecpe_fns[a->esz], a, 0)
 
 static gen_helper_gvec_2_ptr * const frsqrte_fns[] = {
     NULL,                      gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s, gen_helper_gvec_frsqrte_d,
 };
-TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_arg_zz, frsqrte_fns[a->esz], a, 0)
+TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frsqrte_fns[a->esz], a, 0)
 
 /*
  *** SVE Floating Point Compare with Zero Group
@@ -XXX,XX +XXX,XX @@ static bool trans_FADDA(DisasContext *s, arg_rprr_esz *a)
     };                                                              \
     TRANS_FEAT(NAME, aa64_sve, gen_gvec_fpst_arg_zzz, name##_fns[a->esz], a, 0)
 
+#define DO_FP3_AH(NAME, name) \
+    static gen_helper_gvec_3_ptr * const name##_fns[4] = {          \
+        NULL, gen_helper_gvec_##name##_h,                           \
+        gen_helper_gvec_##name##_s, gen_helper_gvec_##name##_d      \
+    };                                                              \
+    TRANS_FEAT(NAME, aa64_sve, gen_gvec_fpst_ah_arg_zzz, name##_fns[a->esz], a, 0)
+
 DO_FP3(FADD_zzz, fadd)
 DO_FP3(FSUB_zzz, fsub)
 DO_FP3(FMUL_zzz, fmul)
-DO_FP3(FRECPS, recps)
-DO_FP3(FRSQRTS, rsqrts)
+DO_FP3_AH(FRECPS, recps)
+DO_FP3_AH(FRSQRTS, rsqrts)
 
 #undef DO_FP3
 
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_3_ptr * const frecpx_fns[] = {
     gen_helper_sve_frecpx_s, gen_helper_sve_frecpx_d,
 };
 TRANS_FEAT(FRECPX, aa64_sve, gen_gvec_fpst_arg_zpz, frecpx_fns[a->esz],
-           a, 0, a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
+           a, 0, select_ah_fpst(s, a->esz))
 
 static gen_helper_gvec_3_ptr * const fsqrt_fns[] = {
     NULL,                   gen_helper_sve_fsqrt_h,
-- 
2.34.1

When FPCR.AH is 1, use FPST_FPCR_AH for:
 * AdvSIMD BFCVT, BFCVTN, BFCVTN2
 * SVE BFCVT, BFCVTNT

so that they get the required behaviour changes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 27 +++++++++++++++++++++------
 target/arm/tcg/translate-sve.c |  6 ++++--
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ TRANS(FRINTX_s, do_fp1_scalar, a, &f_scalar_frintx, -1)
 static const FPScalar1 f_scalar_bfcvt = {
     .gen_s = gen_helper_bfcvt,
 };
-TRANS_FEAT(BFCVT_s, aa64_bf16, do_fp1_scalar, a, &f_scalar_bfcvt, -1)
+TRANS_FEAT(BFCVT_s, aa64_bf16, do_fp1_scalar_ah, a, &f_scalar_bfcvt, -1)
 
 static const FPScalar1 f_scalar_frint32 = {
     NULL,
@@ -XXX,XX +XXX,XX @@ static void gen_bfcvtn_hs(TCGv_i64 d, TCGv_i64 n)
     tcg_gen_extu_i32_i64(d, tmp);
 }
 
-static ArithOneOp * const f_vector_bfcvtn[] = {
-    NULL,
-    gen_bfcvtn_hs,
-    NULL,
+static void gen_bfcvtn_ah_hs(TCGv_i64 d, TCGv_i64 n)
+{
+    TCGv_ptr fpst = fpstatus_ptr(FPST_AH);
+    TCGv_i32 tmp = tcg_temp_new_i32();
+    gen_helper_bfcvt_pair(tmp, n, fpst);
+    tcg_gen_extu_i32_i64(d, tmp);
+}
+
+static ArithOneOp * const f_vector_bfcvtn[2][3] = {
+    {
+        NULL,
+        gen_bfcvtn_hs,
+        NULL,
+    }, {
+        NULL,
+        gen_bfcvtn_ah_hs,
+        NULL,
+    }
 };
-TRANS_FEAT(BFCVTN_v, aa64_bf16, do_2misc_narrow_vector, a, f_vector_bfcvtn)
+TRANS_FEAT(BFCVTN_v, aa64_bf16, do_2misc_narrow_vector, a,
+           f_vector_bfcvtn[s->fpcr_ah])
 
 static bool trans_SHLL_v(DisasContext *s, arg_qrr_e *a)
 {
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ TRANS_FEAT(FCVT_hs, aa64_sve, gen_gvec_fpst_arg_zpz,
            gen_helper_sve_fcvt_hs, a, 0, FPST_A64_F16)
 
 TRANS_FEAT(BFCVT, aa64_sve_bf16, gen_gvec_fpst_arg_zpz,
-           gen_helper_sve_bfcvt, a, 0, FPST_A64)
+           gen_helper_sve_bfcvt, a, 0,
+           s->fpcr_ah ? FPST_AH : FPST_A64)
 
 TRANS_FEAT(FCVT_dh, aa64_sve, gen_gvec_fpst_arg_zpz,
            gen_helper_sve_fcvt_dh, a, 0, FPST_A64)
@@ -XXX,XX +XXX,XX @@ TRANS_FEAT(FCVTNT_ds, aa64_sve2, gen_gvec_fpst_arg_zpz,
            gen_helper_sve2_fcvtnt_ds, a, 0, FPST_A64)
 
 TRANS_FEAT(BFCVTNT, aa64_sve_bf16, gen_gvec_fpst_arg_zpz,
-           gen_helper_sve_bfcvtnt, a, 0, FPST_A64)
+           gen_helper_sve_bfcvtnt, a, 0,
+           s->fpcr_ah ? FPST_AH : FPST_A64)
 
 TRANS_FEAT(FCVTLT_hs, aa64_sve2, gen_gvec_fpst_arg_zpz,
            gen_helper_sve2_fcvtlt_hs, a, 0, FPST_A64)
-- 
2.34.1

When FPCR.AH is 1, use FPST_FPCR_AH for:
 * AdvSIMD BFMLALB, BFMLALT
 * SVE BFMLALB, BFMLALT, BFMLSLB, BFMLSLT

so that they get the required behaviour changes.

We do this by making gen_gvec_op4_fpst() take an ARMFPStatusFlavour
rather than a bool is_fp16; existing callsites now select
FPST_FPCR_F16_A64 vs FPST_FPCR_A64 themselves rather than passing in
the boolean.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 20 +++++++++++++-------
 target/arm/tcg/translate-sve.c |  6 ++++--
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void gen_gvec_op4_env(DisasContext *s, bool is_q, int rd, int rn,
  * an out-of-line helper.
  */
 static void gen_gvec_op4_fpst(DisasContext *s, bool is_q, int rd, int rn,
-                              int rm, int ra, bool is_fp16, int data,
+                              int rm, int ra, ARMFPStatusFlavour fpsttype,
+                              int data,
                               gen_helper_gvec_4_ptr *fn)
 {
-    TCGv_ptr fpst = fpstatus_ptr(is_fp16 ? FPST_A64_F16 : FPST_A64);
+    TCGv_ptr fpst = fpstatus_ptr(fpsttype);
     tcg_gen_gvec_4_ptr(vec_full_reg_offset(s, rd),
                        vec_full_reg_offset(s, rn),
                        vec_full_reg_offset(s, rm),
@@ -XXX,XX +XXX,XX @@ static bool trans_BFMLAL_v(DisasContext *s, arg_qrrr_e *a)
     }
     if (fp_access_check(s)) {
         /* Q bit selects BFMLALB vs BFMLALT. */
-        gen_gvec_op4_fpst(s, true, a->rd, a->rn, a->rm, a->rd, false, a->q,
+        gen_gvec_op4_fpst(s, true, a->rd, a->rn, a->rm, a->rd,
+                          s->fpcr_ah ? FPST_AH : FPST_A64, a->q,
                           gen_helper_gvec_bfmlal);
     }
     return true;
@@ -XXX,XX +XXX,XX @@ static bool trans_FCMLA_v(DisasContext *s, arg_FCMLA_v *a)
     }
 
     gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
-                      a->esz == MO_16, a->rot, fn[a->esz]);
+                      a->esz == MO_16 ? FPST_A64_F16 : FPST_A64,
+                      a->rot, fn[a->esz]);
     return true;
 }
 
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_vector_idx(DisasContext *s, arg_qrrx_e *a, bool neg)
     }
 
     gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
-                      esz == MO_16, (a->idx << 1) | neg,
+                      esz == MO_16 ? FPST_A64_F16 : FPST_A64,
+                      (a->idx << 1) | neg,
                       fns[esz - 1]);
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_BFMLAL_vi(DisasContext *s, arg_qrrx_e *a)
     }
     if (fp_access_check(s)) {
         /* Q bit selects BFMLALB vs BFMLALT. */
-        gen_gvec_op4_fpst(s, true, a->rd, a->rn, a->rm, a->rd, 0,
+        gen_gvec_op4_fpst(s, true, a->rd, a->rn, a->rm, a->rd,
+                          s->fpcr_ah ? FPST_AH : FPST_A64,
                           (a->idx << 1) | a->q,
                           gen_helper_gvec_bfmlal_idx);
     }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCMLA_vi(DisasContext *s, arg_FCMLA_vi *a)
     }
     if (fp_access_check(s)) {
         gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
-                          a->esz == MO_16, (a->idx << 2) | a->rot, fn);
+                          a->esz == MO_16 ? FPST_A64_F16 : FPST_A64,
+                          (a->idx << 2) | a->rot, fn);
     }
     return true;
 }
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ TRANS_FEAT_NONSTREAMING(BFMMLA, aa64_sve_bf16, gen_gvec_env_arg_zzzz,
 static bool do_BFMLAL_zzzw(DisasContext *s, arg_rrrr_esz *a, bool sel)
 {
     return gen_gvec_fpst_zzzz(s, gen_helper_gvec_bfmlal,
-                              a->rd, a->rn, a->rm, a->ra, sel, FPST_A64);
+                              a->rd, a->rn, a->rm, a->ra, sel,
+                              s->fpcr_ah ? FPST_AH : FPST_A64);
 }
 
 TRANS_FEAT(BFMLALB_zzzw, aa64_sve_bf16, do_BFMLAL_zzzw, a, false)
@@ -XXX,XX +XXX,XX @@ static bool do_BFMLAL_zzxw(DisasContext *s, arg_rrxr_esz *a, bool sel)
 {
     return gen_gvec_fpst_zzzz(s, gen_helper_gvec_bfmlal_idx,
                               a->rd, a->rn, a->rm, a->ra,
-                              (a->index << 1) | sel, FPST_A64);
+                              (a->index << 1) | sel,
+                              s->fpcr_ah ? FPST_AH : FPST_A64);
 }
 
 TRANS_FEAT(BFMLALB_zzxw, aa64_sve_bf16, do_BFMLAL_zzxw, a, false)
-- 
2.34.1

For FEAT_AFP, we want to emit different code when FPCR.NEP is set, so
that instead of zeroing the high elements of a vector register when
we write the output of a scalar operation to it, we instead merge in
those elements from one of the source registers.  Since this affects
the generated code, we need to put FPCR.NEP into the TBFLAGS.

FPCR.NEP is treated as 0 when in streaming SVE mode and FEAT_SME_FA64
is not implemented or not enabled; we can implement this logic in
rebuild_hflags_a64().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.h               | 1 +
 target/arm/tcg/translate.h     | 2 ++
 target/arm/tcg/hflags.c        | 9 +++++++++
 target/arm/tcg/translate-a64.c | 1 +
 4 files changed, 13 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ FIELD(TBFLAG_A64, NV2_MEM_E20, 35, 1)
 /* Set if FEAT_NV2 RAM accesses are big-endian */
 FIELD(TBFLAG_A64, NV2_MEM_BE, 36, 1)
 FIELD(TBFLAG_A64, AH, 37, 1)   /* FPCR.AH */
+FIELD(TBFLAG_A64, NEP, 38, 1)   /* FPCR.NEP */
 
 /*
  * Helpers for using the above. Note that only the A64 accessors use
diff --git a/target/arm/tcg/translate.h b/target/arm/tcg/translate.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate.h
+++ b/target/arm/tcg/translate.h
@@ -XXX,XX +XXX,XX @@ typedef struct DisasContext {
     bool nv2_mem_be;
     /* True if FPCR.AH is 1 (alternate floating point handling) */
     bool fpcr_ah;
+    /* True if FPCR.NEP is 1 (FEAT_AFP scalar upper-element result handling) */
+    bool fpcr_nep;
     /*
      * >= 0, a copy of PSTATE.BTYPE, which will be 0 without v8.5-BTI.
      *  < 0, set by the current instruction.
diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/hflags.c
+++ b/target/arm/tcg/hflags.c
@@ -XXX,XX +XXX,XX @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
     if (env->vfp.fpcr & FPCR_AH) {
         DP_TBFLAG_A64(flags, AH, 1);
     }
+    if (env->vfp.fpcr & FPCR_NEP) {
+        /*
+         * In streaming-SVE without FA64, NEP behaves as if zero;
+         * compare pseudocode IsMerging()
+         */
+        if (!(EX_TBFLAG_A64(flags, PSTATE_SM) && !sme_fa64(env, el))) {
+            DP_TBFLAG_A64(flags, NEP, 1);
+        }
+    }
 
     return rebuild_hflags_common(env, fp_el, mmu_idx, flags);
 }
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void aarch64_tr_init_disas_context(DisasContextBase *dcbase,
     dc->nv2_mem_e20 = EX_TBFLAG_A64(tb_flags, NV2_MEM_E20);
     dc->nv2_mem_be = EX_TBFLAG_A64(tb_flags, NV2_MEM_BE);
     dc->fpcr_ah = EX_TBFLAG_A64(tb_flags, AH);
+    dc->fpcr_nep = EX_TBFLAG_A64(tb_flags, NEP);
     dc->vec_len = 0;
     dc->vec_stride = 0;
     dc->cp_regs = arm_cpu->cp_regs;
-- 
2.34.1

For FEAT_AFP's FPCR.NEP bit, we need to programmatically change the
behaviour of the writeback of the result for most SIMD scalar
operations, so that instead of zeroing the upper part of the result
register it merges the upper elements from one of the input
registers.

Provide new functions write_fp_*reg_merging() which can be used
instead of the existing write_fp_*reg() functions when we want this
"merge the result with one of the input registers if FPCR.NEP is
enabled" handling, and use them in do_fp3_scalar_with_fpsttype().

Note that (as documented in the description of the FPCR.NEP bit)
which input register to use as the merge source varies by
instruction: for these 2-input scalar operations, the comparison
instructions take from Rm, not Rn.

We'll extend this to also provide the merging behaviour for
the remaining scalar insns in subsequent commits.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 117 +++++++++++++++++++++++++--------
 1 file changed, 91 insertions(+), 26 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void write_fp_sreg(DisasContext *s, int reg, TCGv_i32 v)
     write_fp_dreg(s, reg, tmp);
 }
 
+/*
+ * Write a double result to 128 bit vector register reg, honouring FPCR.NEP:
+ * - if FPCR.NEP == 0, clear the high elements of reg
+ * - if FPCR.NEP == 1, set the high elements of reg from mergereg
+ *   (i.e. merge the result with those high elements)
+ * In either case, SVE register bits above 128 are zeroed (per R_WKYLB).
+ */
+static void write_fp_dreg_merging(DisasContext *s, int reg, int mergereg,
+                                  TCGv_i64 v)
+{
+    if (!s->fpcr_nep) {
+        write_fp_dreg(s, reg, v);
+        return;
+    }
+
+    /*
+     * Move from mergereg to reg; this sets the high elements and
+     * clears the bits above 128 as a side effect.
+     */
+    tcg_gen_gvec_mov(MO_64, vec_full_reg_offset(s, reg),
+                     vec_full_reg_offset(s, mergereg),
+                     16, vec_full_reg_size(s));
+    tcg_gen_st_i64(v, tcg_env, vec_full_reg_offset(s, reg));
+}
+
+/*
+ * Write a single-prec result, but only clear the higher elements
+ * of the destination register if FPCR.NEP is 0; otherwise preserve them.
+ */
+static void write_fp_sreg_merging(DisasContext *s, int reg, int mergereg,
+                                  TCGv_i32 v)
+{
+    if (!s->fpcr_nep) {
+        write_fp_sreg(s, reg, v);
+        return;
+    }
+
+    tcg_gen_gvec_mov(MO_64, vec_full_reg_offset(s, reg),
+                     vec_full_reg_offset(s, mergereg),
+                     16, vec_full_reg_size(s));
+    tcg_gen_st_i32(v, tcg_env, fp_reg_offset(s, reg, MO_32));
+}
+
+/*
+ * Write a half-prec result, but only clear the higher elements
+ * of the destination register if FPCR.NEP is 0; otherwise preserve them.
+ * The caller must ensure that the top 16 bits of v are zero.
+ */
+static void write_fp_hreg_merging(DisasContext *s, int reg, int mergereg,
+                                  TCGv_i32 v)
+{
+    if (!s->fpcr_nep) {
+        write_fp_sreg(s, reg, v);
+        return;
+    }
+
+    tcg_gen_gvec_mov(MO_64, vec_full_reg_offset(s, reg),
+                     vec_full_reg_offset(s, mergereg),
+                     16, vec_full_reg_size(s));
+    tcg_gen_st16_i32(v, tcg_env, fp_reg_offset(s, reg, MO_16));
+}
+
 /* Expand a 2-operand AdvSIMD vector operation using an expander function.  */
 static void gen_gvec_fn2(DisasContext *s, bool is_q, int rd, int rn,
                          GVecGen2Fn *gvec_fn, int vece)
@@ -XXX,XX +XXX,XX @@ typedef struct FPScalar {
 } FPScalar;
 
 static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
-                                        const FPScalar *f,
+                                        const FPScalar *f, int mergereg,
                                         ARMFPStatusFlavour fpsttype)
 {
     switch (a->esz) {
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
             TCGv_i64 t0 = read_fp_dreg(s, a->rn);
             TCGv_i64 t1 = read_fp_dreg(s, a->rm);
             f->gen_d(t0, t0, t1, fpstatus_ptr(fpsttype));
-            write_fp_dreg(s, a->rd, t0);
+            write_fp_dreg_merging(s, a->rd, mergereg, t0);
         }
         break;
     case MO_32:
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
             TCGv_i32 t0 = read_fp_sreg(s, a->rn);
             TCGv_i32 t1 = read_fp_sreg(s, a->rm);
             f->gen_s(t0, t0, t1, fpstatus_ptr(fpsttype));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_sreg_merging(s, a->rd, mergereg, t0);
         }
         break;
     case MO_16:
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
             TCGv_i32 t0 = read_fp_hreg(s, a->rn);
             TCGv_i32 t1 = read_fp_hreg(s, a->rm);
             f->gen_h(t0, t0, t1, fpstatus_ptr(fpsttype));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_hreg_merging(s, a->rd, mergereg, t0);
         }
         break;
     default:
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_with_fpsttype(DisasContext *s, arg_rrr_e *a,
     return true;
 }
 
-static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
+static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f,
+                          int mergereg)
 {
-    return do_fp3_scalar_with_fpsttype(s, a, f,
+    return do_fp3_scalar_with_fpsttype(s, a, f, mergereg,
                                        a->esz == MO_16 ?
                                        FPST_A64_F16 : FPST_A64);
 }
 
-static bool do_fp3_scalar_ah(DisasContext *s, arg_rrr_e *a, const FPScalar *f)
+static bool do_fp3_scalar_ah(DisasContext *s, arg_rrr_e *a, const FPScalar *f,
+                             int mergereg)
 {
-    return do_fp3_scalar_with_fpsttype(s, a, f, select_ah_fpst(s, a->esz));
+    return do_fp3_scalar_with_fpsttype(s, a, f, mergereg,
+                                       select_ah_fpst(s, a->esz));
 }
 
 static const FPScalar f_scalar_fadd = {
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_fadd = {
     gen_helper_vfp_adds,
     gen_helper_vfp_addd,
 };
-TRANS(FADD_s, do_fp3_scalar, a, &f_scalar_fadd)
+TRANS(FADD_s, do_fp3_scalar, a, &f_scalar_fadd, a->rn)
 
 static const FPScalar f_scalar_fsub = {
     gen_helper_vfp_subh,
     gen_helper_vfp_subs,
     gen_helper_vfp_subd,
 };
-TRANS(FSUB_s, do_fp3_scalar, a, &f_scalar_fsub)
+TRANS(FSUB_s, do_fp3_scalar, a, &f_scalar_fsub, a->rn)
 
 static const FPScalar f_scalar_fdiv = {
     gen_helper_vfp_divh,
     gen_helper_vfp_divs,
     gen_helper_vfp_divd,
 };
-TRANS(FDIV_s, do_fp3_scalar, a, &f_scalar_fdiv)
+TRANS(FDIV_s, do_fp3_scalar, a, &f_scalar_fdiv, a->rn)
 
 static const FPScalar f_scalar_fmul = {
     gen_helper_vfp_mulh,
     gen_helper_vfp_muls,
     gen_helper_vfp_muld,
 };
-TRANS(FMUL_s, do_fp3_scalar, a, &f_scalar_fmul)
+TRANS(FMUL_s, do_fp3_scalar, a, &f_scalar_fmul, a->rn)
 
 static const FPScalar f_scalar_fmax = {
     gen_helper_vfp_maxh,
     gen_helper_vfp_maxs,
     gen_helper_vfp_maxd,
 };
-TRANS(FMAX_s, do_fp3_scalar, a, &f_scalar_fmax)
+TRANS(FMAX_s, do_fp3_scalar, a, &f_scalar_fmax, a->rn)
 
 static const FPScalar f_scalar_fmin = {
     gen_helper_vfp_minh,
     gen_helper_vfp_mins,
     gen_helper_vfp_mind,
 };
-TRANS(FMIN_s, do_fp3_scalar, a, &f_scalar_fmin)
+TRANS(FMIN_s, do_fp3_scalar, a, &f_scalar_fmin, a->rn)
 
 static const FPScalar f_scalar_fmaxnm = {
     gen_helper_vfp_maxnumh,
     gen_helper_vfp_maxnums,
     gen_helper_vfp_maxnumd,
 };
-TRANS(FMAXNM_s, do_fp3_scalar, a, &f_scalar_fmaxnm)
+TRANS(FMAXNM_s, do_fp3_scalar, a, &f_scalar_fmaxnm, a->rn)
 
 static const FPScalar f_scalar_fminnm = {
     gen_helper_vfp_minnumh,
     gen_helper_vfp_minnums,
     gen_helper_vfp_minnumd,
 };
-TRANS(FMINNM_s, do_fp3_scalar, a, &f_scalar_fminnm)
+TRANS(FMINNM_s, do_fp3_scalar, a, &f_scalar_fminnm, a->rn)
 
 static const FPScalar f_scalar_fmulx = {
     gen_helper_advsimd_mulxh,
     gen_helper_vfp_mulxs,
     gen_helper_vfp_mulxd,
 };
-TRANS(FMULX_s, do_fp3_scalar, a, &f_scalar_fmulx)
+TRANS(FMULX_s, do_fp3_scalar, a, &f_scalar_fmulx, a->rn)
 
 static void gen_fnmul_h(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
 {
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_fnmul = {
     gen_fnmul_s,
     gen_fnmul_d,
 };
-TRANS(FNMUL_s, do_fp3_scalar, a, &f_scalar_fnmul)
+TRANS(FNMUL_s, do_fp3_scalar, a, &f_scalar_fnmul, a->rn)
 
 static const FPScalar f_scalar_fcmeq = {
     gen_helper_advsimd_ceq_f16,
     gen_helper_neon_ceq_f32,
     gen_helper_neon_ceq_f64,
 };
-TRANS(FCMEQ_s, do_fp3_scalar, a, &f_scalar_fcmeq)
+TRANS(FCMEQ_s, do_fp3_scalar, a, &f_scalar_fcmeq, a->rm)
 
 static const FPScalar f_scalar_fcmge = {
     gen_helper_advsimd_cge_f16,
     gen_helper_neon_cge_f32,
     gen_helper_neon_cge_f64,
 };
-TRANS(FCMGE_s, do_fp3_scalar, a, &f_scalar_fcmge)
+TRANS(FCMGE_s, do_fp3_scalar, a, &f_scalar_fcmge, a->rm)
 
 static const FPScalar f_scalar_fcmgt = {
     gen_helper_advsimd_cgt_f16,
     gen_helper_neon_cgt_f32,
     gen_helper_neon_cgt_f64,
 };
-TRANS(FCMGT_s, do_fp3_scalar, a, &f_scalar_fcmgt)
+TRANS(FCMGT_s, do_fp3_scalar, a, &f_scalar_fcmgt, a->rm)
 
 static const FPScalar f_scalar_facge = {
     gen_helper_advsimd_acge_f16,
     gen_helper_neon_acge_f32,
     gen_helper_neon_acge_f64,
 };
-TRANS(FACGE_s, do_fp3_scalar, a, &f_scalar_facge)
+TRANS(FACGE_s, do_fp3_scalar, a, &f_scalar_facge, a->rm)
 
 static const FPScalar f_scalar_facgt = {
     gen_helper_advsimd_acgt_f16,
     gen_helper_neon_acgt_f32,
     gen_helper_neon_acgt_f64,
 };
-TRANS(FACGT_s, do_fp3_scalar, a, &f_scalar_facgt)
+TRANS(FACGT_s, do_fp3_scalar, a, &f_scalar_facgt, a->rm)
 
 static void gen_fabd_h(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
 {
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_fabd = {
     gen_fabd_s,
     gen_fabd_d,
 };
-TRANS(FABD_s, do_fp3_scalar, a, &f_scalar_fabd)
+TRANS(FABD_s, do_fp3_scalar, a, &f_scalar_fabd, a->rn)
 
 static const FPScalar f_scalar_frecps = {
     gen_helper_recpsf_f16,
     gen_helper_recpsf_f32,
     gen_helper_recpsf_f64,
 };
-TRANS(FRECPS_s, do_fp3_scalar_ah, a, &f_scalar_frecps)
+TRANS(FRECPS_s, do_fp3_scalar_ah, a, &f_scalar_frecps, a->rn)
 
 static const FPScalar f_scalar_frsqrts = {
     gen_helper_rsqrtsf_f16,
     gen_helper_rsqrtsf_f32,
     gen_helper_rsqrtsf_f64,
 };
-TRANS(FRSQRTS_s, do_fp3_scalar_ah, a, &f_scalar_frsqrts)
+TRANS(FRSQRTS_s, do_fp3_scalar_ah, a, &f_scalar_frsqrts, a->rn)
 
 static bool do_fcmp0_s(DisasContext *s, arg_rr_e *a,
                        const FPScalar *f, bool swap)
-- 
2.34.1

Handle FPCR.NEP for the 3-input scalar operations which use
do_fmla_scalar_idx() and do_fmadd(), by making them call the
appropriate write_fp_*reg_merging() functions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
                 gen_vfp_negd(t1, t1);
             }
             gen_helper_vfp_muladdd(t0, t1, t2, t0, fpstatus_ptr(FPST_A64));
-            write_fp_dreg(s, a->rd, t0);
+            write_fp_dreg_merging(s, a->rd, a->rd, t0);
         }
         break;
     case MO_32:
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
                 gen_vfp_negs(t1, t1);
             }
             gen_helper_vfp_muladds(t0, t1, t2, t0, fpstatus_ptr(FPST_A64));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_sreg_merging(s, a->rd, a->rd, t0);
         }
         break;
     case MO_16:
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
             }
             gen_helper_advsimd_muladdh(t0, t1, t2, t0,
                                        fpstatus_ptr(FPST_A64_F16));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_hreg_merging(s, a->rd, a->rd, t0);
         }
         break;
     default:
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             }
             fpst = fpstatus_ptr(FPST_A64);
             gen_helper_vfp_muladdd(ta, tn, tm, ta, fpst);
-            write_fp_dreg(s, a->rd, ta);
+            write_fp_dreg_merging(s, a->rd, a->ra, ta);
         }
         break;
 
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             }
             fpst = fpstatus_ptr(FPST_A64);
             gen_helper_vfp_muladds(ta, tn, tm, ta, fpst);
-            write_fp_sreg(s, a->rd, ta);
+            write_fp_sreg_merging(s, a->rd, a->ra, ta);
         }
         break;
 
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             }
             fpst = fpstatus_ptr(FPST_A64_F16);
             gen_helper_advsimd_muladdh(ta, tn, tm, ta, fpst);
-            write_fp_sreg(s, a->rd, ta);
+            write_fp_hreg_merging(s, a->rd, a->ra, ta);
         }
         break;
 
-- 
2.34.1

Currently we implement BFCVT scalar via do_fp1_scalar().  This works
even though BFCVT is a narrowing operation from 32 to 16 bits,
because we can use write_fp_sreg() for float16. However, FPCR.NEP
support requires that we use write_fp_hreg_merging() for float16
outputs, so we can't continue to borrow the non-narrowing
do_fp1_scalar() function for this. Split out trans_BFCVT_s()
into its own implementation that honours FPCR.NEP.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static const FPScalar1 f_scalar_frintx = {
 };
 TRANS(FRINTX_s, do_fp1_scalar, a, &f_scalar_frintx, -1)
 
-static const FPScalar1 f_scalar_bfcvt = {
-    .gen_s = gen_helper_bfcvt,
-};
-TRANS_FEAT(BFCVT_s, aa64_bf16, do_fp1_scalar_ah, a, &f_scalar_bfcvt, -1)
+static bool trans_BFCVT_s(DisasContext *s, arg_rr_e *a)
+{
+    ARMFPStatusFlavour fpsttype = s->fpcr_ah ? FPST_AH : FPST_A64;
+    TCGv_i32 t32;
+    int check;
+
+    if (!dc_isar_feature(aa64_bf16, s)) {
+        return false;
+    }
+
+    check = fp_access_check_scalar_hsd(s, a->esz);
+
+    if (check <= 0) {
+        return check == 0;
+    }
+
+    t32 = read_fp_sreg(s, a->rn);
+    gen_helper_bfcvt(t32, t32, fpstatus_ptr(fpsttype));
+    write_fp_hreg_merging(s, a->rd, a->rd, t32);
+    return true;
+}
 
 static const FPScalar1 f_scalar_frint32 = {
     NULL,
-- 
2.34.1

Handle FPCR.NEP for the 1-input scalar operations.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_fp1_scalar_with_fpsttype(DisasContext *s, arg_rr_e *a,
     case MO_64:
         t64 = read_fp_dreg(s, a->rn);
         f->gen_d(t64, t64, fpst);
-        write_fp_dreg(s, a->rd, t64);
+        write_fp_dreg_merging(s, a->rd, a->rd, t64);
         break;
     case MO_32:
         t32 = read_fp_sreg(s, a->rn);
         f->gen_s(t32, t32, fpst);
-        write_fp_sreg(s, a->rd, t32);
+        write_fp_sreg_merging(s, a->rd, a->rd, t32);
         break;
     case MO_16:
         t32 = read_fp_hreg(s, a->rn);
         f->gen_h(t32, t32, fpst);
-        write_fp_sreg(s, a->rd, t32);
+        write_fp_hreg_merging(s, a->rd, a->rd, t32);
         break;
     default:
         g_assert_not_reached();
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_ds(DisasContext *s, arg_rr *a)
         TCGv_ptr fpst = fpstatus_ptr(FPST_A64);
 
         gen_helper_vfp_fcvtds(tcg_rd, tcg_rn, fpst);
-        write_fp_dreg(s, a->rd, tcg_rd);
+        write_fp_dreg_merging(s, a->rd, a->rd, tcg_rd);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_hs(DisasContext *s, arg_rr *a)
         TCGv_ptr fpst = fpstatus_ptr(FPST_A64);
 
         gen_helper_vfp_fcvt_f32_to_f16(tmp, tmp, fpst, ahp);
-        /* write_fp_sreg is OK here because top half of result is zero */
-        write_fp_sreg(s, a->rd, tmp);
+        /* write_fp_hreg_merging is OK here because top half of result is zero */
+        write_fp_hreg_merging(s, a->rd, a->rd, tmp);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_sd(DisasContext *s, arg_rr *a)
         TCGv_ptr fpst = fpstatus_ptr(FPST_A64);
 
         gen_helper_vfp_fcvtsd(tcg_rd, tcg_rn, fpst);
-        write_fp_sreg(s, a->rd, tcg_rd);
+        write_fp_sreg_merging(s, a->rd, a->rd, tcg_rd);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_hd(DisasContext *s, arg_rr *a)
         TCGv_ptr fpst = fpstatus_ptr(FPST_A64);
 
         gen_helper_vfp_fcvt_f64_to_f16(tcg_rd, tcg_rn, fpst, ahp);
-        /* write_fp_sreg is OK here because top half of tcg_rd is zero */
-        write_fp_sreg(s, a->rd, tcg_rd);
+        /* write_fp_hreg_merging is OK here because top half of tcg_rd is zero */
+        write_fp_hreg_merging(s, a->rd, a->rd, tcg_rd);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_sh(DisasContext *s, arg_rr *a)
         TCGv_i32 tcg_ahp = get_ahp_flag();
 
         gen_helper_vfp_fcvt_f16_to_f32(tcg_rd, tcg_rn, tcg_fpst, tcg_ahp);
-        write_fp_sreg(s, a->rd, tcg_rd);
+        write_fp_sreg_merging(s, a->rd, a->rd, tcg_rd);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool trans_FCVT_s_dh(DisasContext *s, arg_rr *a)
         TCGv_i32 tcg_ahp = get_ahp_flag();
 
         gen_helper_vfp_fcvt_f16_to_f64(tcg_rd, tcg_rn, tcg_fpst, tcg_ahp);
-        write_fp_dreg(s, a->rd, tcg_rd);
+        write_fp_dreg_merging(s, a->rd, a->rd, tcg_rd);
     }
     return true;
 }
@@ -XXX,XX +XXX,XX @@ static bool do_fcvt_f(DisasContext *s, arg_fcvt *a,
     do_fcvt_scalar(s, a->esz | (is_signed ? MO_SIGN : 0),
                    a->esz, tcg_int, a->shift, a->rn, rmode);
 
-    clear_vec(s, a->rd);
+    if (!s->fpcr_nep) {
+        clear_vec(s, a->rd);
+    }
     write_vec_element(s, tcg_int, a->rd, 0, a->esz);
     return true;
 }
-- 
2.34.1

Handle FPCR.NEP in the operations handled by do_cvtf_scalar().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_cvtf_scalar(DisasContext *s, MemOp esz, int rd, int shift,
         } else {
             gen_helper_vfp_uqtod(tcg_double, tcg_int, tcg_shift, tcg_fpstatus);
         }
-        write_fp_dreg(s, rd, tcg_double);
+        write_fp_dreg_merging(s, rd, rd, tcg_double);
         break;
 
     case MO_32:
@@ -XXX,XX +XXX,XX @@ static bool do_cvtf_scalar(DisasContext *s, MemOp esz, int rd, int shift,
         } else {
             gen_helper_vfp_uqtos(tcg_single, tcg_int, tcg_shift, tcg_fpstatus);
         }
-        write_fp_sreg(s, rd, tcg_single);
+        write_fp_sreg_merging(s, rd, rd, tcg_single);
         break;
 
     case MO_16:
@@ -XXX,XX +XXX,XX @@ static bool do_cvtf_scalar(DisasContext *s, MemOp esz, int rd, int shift,
         } else {
             gen_helper_vfp_uqtoh(tcg_single, tcg_int, tcg_shift, tcg_fpstatus);
         }
-        write_fp_sreg(s, rd, tcg_single);
+        write_fp_hreg_merging(s, rd, rd, tcg_single);
         break;
 
     default:
-- 
2.34.1

Handle FPCR.NEP merging for scalar FABS and FNEG; this requires
an extra parameter to do_fp1_scalar_int(), since FMOV scalar
does not have the merging behaviour.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ typedef struct FPScalar1Int {
 } FPScalar1Int;
 
 static bool do_fp1_scalar_int(DisasContext *s, arg_rr_e *a,
-                              const FPScalar1Int *f)
+                              const FPScalar1Int *f,
+                              bool merging)
 {
     switch (a->esz) {
     case MO_64:
         if (fp_access_check(s)) {
             TCGv_i64 t = read_fp_dreg(s, a->rn);
             f->gen_d(t, t);
-            write_fp_dreg(s, a->rd, t);
+            if (merging) {
+                write_fp_dreg_merging(s, a->rd, a->rd, t);
+            } else {
+                write_fp_dreg(s, a->rd, t);
+            }
         }
         break;
     case MO_32:
         if (fp_access_check(s)) {
             TCGv_i32 t = read_fp_sreg(s, a->rn);
             f->gen_s(t, t);
-            write_fp_sreg(s, a->rd, t);
+            if (merging) {
+                write_fp_sreg_merging(s, a->rd, a->rd, t);
+            } else {
+                write_fp_sreg(s, a->rd, t);
+            }
         }
         break;
     case MO_16:
@@ -XXX,XX +XXX,XX @@ static bool do_fp1_scalar_int(DisasContext *s, arg_rr_e *a,
         if (fp_access_check(s)) {
             TCGv_i32 t = read_fp_hreg(s, a->rn);
             f->gen_h(t, t);
-            write_fp_sreg(s, a->rd, t);
+            if (merging) {
+                write_fp_hreg_merging(s, a->rd, a->rd, t);
+            } else {
+                write_fp_sreg(s, a->rd, t);
+            }
         }
         break;
     default:
@@ -XXX,XX +XXX,XX @@ static const FPScalar1Int f_scalar_fmov = {
     tcg_gen_mov_i32,
     tcg_gen_mov_i64,
 };
-TRANS(FMOV_s, do_fp1_scalar_int, a, &f_scalar_fmov)
+TRANS(FMOV_s, do_fp1_scalar_int, a, &f_scalar_fmov, false)
 
 static const FPScalar1Int f_scalar_fabs = {
     gen_vfp_absh,
     gen_vfp_abss,
     gen_vfp_absd,
 };
-TRANS(FABS_s, do_fp1_scalar_int, a, &f_scalar_fabs)
+TRANS(FABS_s, do_fp1_scalar_int, a, &f_scalar_fabs, true)
 
 static const FPScalar1Int f_scalar_fneg = {
     gen_vfp_negh,
     gen_vfp_negs,
     gen_vfp_negd,
 };
-TRANS(FNEG_s, do_fp1_scalar_int, a, &f_scalar_fneg)
+TRANS(FNEG_s, do_fp1_scalar_int, a, &f_scalar_fneg, true)
 
 typedef struct FPScalar1 {
     void (*gen_h)(TCGv_i32, TCGv_i32, TCGv_ptr);
-- 
2.34.1

Unlike the other users of do_2misc_narrow_scalar(), FCVTXN (scalar)
is always double-to-single and must honour FPCR.NEP.  Implement this
directly in a trans function rather than using
do_2misc_narrow_scalar().

We still need gen_fcvtxn_sd() and the f_scalar_fcvtxn[] array for
the FCVTXN (vector) insn, so we move those down in the file to
where they are used.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 43 ++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 15 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static ArithOneOp * const f_scalar_uqxtn[] = {
 };
 TRANS(UQXTN_s, do_2misc_narrow_scalar, a, f_scalar_uqxtn)
 
-static void gen_fcvtxn_sd(TCGv_i64 d, TCGv_i64 n)
+static bool trans_FCVTXN_s(DisasContext *s, arg_rr_e *a)
 {
-    /*
-     * 64 bit to 32 bit float conversion
-     * with von Neumann rounding (round to odd)
-     */
-    TCGv_i32 tmp = tcg_temp_new_i32();
-    gen_helper_fcvtx_f64_to_f32(tmp, n, fpstatus_ptr(FPST_A64));
-    tcg_gen_extu_i32_i64(d, tmp);
+    if (fp_access_check(s)) {
+        /*
+         * 64 bit to 32 bit float conversion
+         * with von Neumann rounding (round to odd)
+         */
+        TCGv_i64 src = read_fp_dreg(s, a->rn);
+        TCGv_i32 dst = tcg_temp_new_i32();
+        gen_helper_fcvtx_f64_to_f32(dst, src, fpstatus_ptr(FPST_A64));
+        write_fp_sreg_merging(s, a->rd, a->rd, dst);
+    }
+    return true;
 }
 
-static ArithOneOp * const f_scalar_fcvtxn[] = {
-    NULL,
-    NULL,
-    gen_fcvtxn_sd,
-};
-TRANS(FCVTXN_s, do_2misc_narrow_scalar, a, f_scalar_fcvtxn)
-
 #undef WRAP_ENV
 
 static bool do_gvec_fn2(DisasContext *s, arg_qrr_e *a, GVecGen2Fn *fn)
@@ -XXX,XX +XXX,XX @@ static void gen_fcvtn_sd(TCGv_i64 d, TCGv_i64 n)
     tcg_gen_extu_i32_i64(d, tmp);
 }
 
+static void gen_fcvtxn_sd(TCGv_i64 d, TCGv_i64 n)
+{
+    /*
+     * 64 bit to 32 bit float conversion
+     * with von Neumann rounding (round to odd)
+     */
+    TCGv_i32 tmp = tcg_temp_new_i32();
+    gen_helper_fcvtx_f64_to_f32(tmp, n, fpstatus_ptr(FPST_A64));
+    tcg_gen_extu_i32_i64(d, tmp);
+}
+
 static ArithOneOp * const f_vector_fcvtn[] = {
     NULL,
     gen_fcvtn_hs,
     gen_fcvtn_sd,
 };
+static ArithOneOp * const f_scalar_fcvtxn[] = {
+    NULL,
+    NULL,
+    gen_fcvtxn_sd,
+};
 TRANS(FCVTN_v, do_2misc_narrow_vector, a, f_vector_fcvtn)
 TRANS(FCVTXN_v, do_2misc_narrow_vector, a, f_scalar_fcvtxn)
 
-- 
2.34.1

do_fp3_scalar_idx() is used only for the FMUL and FMULX scalar by
element instructions; these both need to merge the result with the Rn
register when FPCR.NEP is set.

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_idx(DisasContext *s, arg_rrx_e *a, const FPScalar *f)
 
             read_vec_element(s, t1, a->rm, a->idx, MO_64);
             f->gen_d(t0, t0, t1, fpstatus_ptr(FPST_A64));
-            write_fp_dreg(s, a->rd, t0);
+            write_fp_dreg_merging(s, a->rd, a->rn, t0);
         }
         break;
     case MO_32:
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_idx(DisasContext *s, arg_rrx_e *a, const FPScalar *f)
 
             read_vec_element_i32(s, t1, a->rm, a->idx, MO_32);
             f->gen_s(t0, t0, t1, fpstatus_ptr(FPST_A64));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_sreg_merging(s, a->rd, a->rn, t0);
         }
         break;
     case MO_16:
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_idx(DisasContext *s, arg_rrx_e *a, const FPScalar *f)
 
             read_vec_element_i32(s, t1, a->rm, a->idx, MO_16);
             f->gen_h(t0, t0, t1, fpstatus_ptr(FPST_A64_F16));
-            write_fp_sreg(s, a->rd, t0);
+            write_fp_hreg_merging(s, a->rd, a->rn, t0);
         }
         break;
     default:
-- 
2.34.1

When FPCR.AH == 1, floating point FMIN and FMAX have some odd special
cases:

* comparing two zeroes (even of different sign) or comparing a NaN
   with anything always returns the second argument (possibly
   squashed to zero)
 * denormal outputs are not squashed to zero regardless of FZ or FZ16

Implement these semantics in new helper functions and select them at
translate time if FPCR.AH is 1 for the scalar FMAX and FMIN insns.
(We will convert the other FMAX and FMIN insns in subsequent
commits.)

Note that FMINNM and FMAXNM are not affected.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-a64.h    |  7 +++++++
 target/arm/tcg/helper-a64.c    | 36 ++++++++++++++++++++++++++++++++++
 target/arm/tcg/translate-a64.c | 23 ++++++++++++++++++++--
 3 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/target/arm/tcg/helper-a64.h b/target/arm/tcg/helper-a64.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/helper-a64.h
+++ b/target/arm/tcg/helper-a64.h
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_4(advsimd_muladd2h, i32, i32, i32, i32, fpst)
 DEF_HELPER_2(advsimd_rinth_exact, f16, f16, fpst)
 DEF_HELPER_2(advsimd_rinth, f16, f16, fpst)
 
+DEF_HELPER_3(vfp_ah_minh, f16, f16, f16, fpst)
+DEF_HELPER_3(vfp_ah_mins, f32, f32, f32, fpst)
+DEF_HELPER_3(vfp_ah_mind, f64, f64, f64, fpst)
+DEF_HELPER_3(vfp_ah_maxh, f16, f16, f16, fpst)
+DEF_HELPER_3(vfp_ah_maxs, f32, f32, f32, fpst)
+DEF_HELPER_3(vfp_ah_maxd, f64, f64, f64, fpst)
+
 DEF_HELPER_2(exception_return, void, env, i64)
 DEF_HELPER_FLAGS_2(dc_zva, TCG_CALL_NO_WG, void, env, i64)
 
diff --git a/target/arm/tcg/helper-a64.c b/target/arm/tcg/helper-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/helper-a64.c
+++ b/target/arm/tcg/helper-a64.c
@@ -XXX,XX +XXX,XX @@ float32 HELPER(fcvtx_f64_to_f32)(float64 a, float_status *fpst)
     return r;
 }
 
+/*
+ * AH=1 min/max have some odd special cases:
+ * comparing two zeroes (regardless of sign), (NaN, anything),
+ * or (anything, NaN) should return the second argument (possibly
+ * squashed to zero).
+ * Also, denormal outputs are not squashed to zero regardless of FZ or FZ16.
+ */
+#define AH_MINMAX_HELPER(NAME, CTYPE, FLOATTYPE, MINMAX)                \
+    CTYPE HELPER(NAME)(CTYPE a, CTYPE b, float_status *fpst)            \
+    {                                                                   \
+        bool save;                                                      \
+        CTYPE r;                                                        \
+        a = FLOATTYPE ## _squash_input_denormal(a, fpst);               \
+        b = FLOATTYPE ## _squash_input_denormal(b, fpst);               \
+        if (FLOATTYPE ## _is_zero(a) && FLOATTYPE ## _is_zero(b)) {     \
+            return b;                                                   \
+        }                                                               \
+        if (FLOATTYPE ## _is_any_nan(a) ||                              \
+            FLOATTYPE ## _is_any_nan(b)) {                              \
+            float_raise(float_flag_invalid, fpst);                      \
+            return b;                                                   \
+        }                                                               \
+        save = get_flush_to_zero(fpst);                                 \
+        set_flush_to_zero(false, fpst);                                 \
+        r = FLOATTYPE ## _ ## MINMAX(a, b, fpst);                       \
+        set_flush_to_zero(save, fpst);                                  \
+        return r;                                                       \
+    }
+
+AH_MINMAX_HELPER(vfp_ah_minh, dh_ctype_f16, float16, min)
+AH_MINMAX_HELPER(vfp_ah_mins, float32, float32, min)
+AH_MINMAX_HELPER(vfp_ah_mind, float64, float64, min)
+AH_MINMAX_HELPER(vfp_ah_maxh, dh_ctype_f16, float16, max)
+AH_MINMAX_HELPER(vfp_ah_maxs, float32, float32, max)
+AH_MINMAX_HELPER(vfp_ah_maxd, float64, float64, max)
+
 /* 64-bit versions of the CRC helpers. Note that although the operation
  * (and the prototypes of crc32c() and crc32() mean that only the bottom
  * 32 bits of the accumulator and result are used, we pass and return
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar_ah(DisasContext *s, arg_rrr_e *a, const FPScalar *f,
                                        select_ah_fpst(s, a->esz));
 }
 
+/* Some insns need to call different helpers when FPCR.AH == 1 */
+static bool do_fp3_scalar_2fn(DisasContext *s, arg_rrr_e *a,
+                              const FPScalar *fnormal,
+                              const FPScalar *fah,
+                              int mergereg)
+{
+    return do_fp3_scalar(s, a, s->fpcr_ah ? fah : fnormal, mergereg);
+}
+
 static const FPScalar f_scalar_fadd = {
     gen_helper_vfp_addh,
     gen_helper_vfp_adds,
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_fmax = {
     gen_helper_vfp_maxs,
     gen_helper_vfp_maxd,
 };
-TRANS(FMAX_s, do_fp3_scalar, a, &f_scalar_fmax, a->rn)
+static const FPScalar f_scalar_fmax_ah = {
+    gen_helper_vfp_ah_maxh,
+    gen_helper_vfp_ah_maxs,
+    gen_helper_vfp_ah_maxd,
+};
+TRANS(FMAX_s, do_fp3_scalar_2fn, a, &f_scalar_fmax, &f_scalar_fmax_ah, a->rn)
 
 static const FPScalar f_scalar_fmin = {
     gen_helper_vfp_minh,
     gen_helper_vfp_mins,
     gen_helper_vfp_mind,
 };
-TRANS(FMIN_s, do_fp3_scalar, a, &f_scalar_fmin, a->rn)
+static const FPScalar f_scalar_fmin_ah = {
+    gen_helper_vfp_ah_minh,
+    gen_helper_vfp_ah_mins,
+    gen_helper_vfp_ah_mind,
+};
+TRANS(FMIN_s, do_fp3_scalar_2fn, a, &f_scalar_fmin, &f_scalar_fmin_ah, a->rn)
 
 static const FPScalar f_scalar_fmaxnm = {
     gen_helper_vfp_maxnumh,
-- 
2.34.1

Implement the FPCR.AH == 1 semantics for vector FMIN/FMAX, by
creating new _ah_ versions of the gvec helpers which invoke the
scalar fmin_ah and fmax_ah helpers on each element.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 ++++++++++++++
 target/arm/tcg/translate-a64.c | 21 +++++++++++++++++++--
 target/arm/tcg/vec_helper.c    |  8 ++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)

Implement the FPCR.AH semantics for FMAXV and FMINV.  These are the
"recursively reduce all lanes of a vector to a scalar result" insns;
we just need to use the _ah_ helper for the reduction step when
FPCR.AH == 1.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static TCGv_i32 do_reduction_op(DisasContext *s, int rn, MemOp esz,
 }
 
 static bool do_fp_reduction(DisasContext *s, arg_qrr_e *a,
-                              NeonGenTwoSingleOpFn *fn)
+                            NeonGenTwoSingleOpFn *fnormal,
+                            NeonGenTwoSingleOpFn *fah)
 {
     if (fp_access_check(s)) {
         MemOp esz = a->esz;
         int elts = (a->q ? 16 : 8) >> esz;
         TCGv_ptr fpst = fpstatus_ptr(esz == MO_16 ? FPST_A64_F16 : FPST_A64);
-        TCGv_i32 res = do_reduction_op(s, a->rn, esz, 0, elts, fpst, fn);
+        TCGv_i32 res = do_reduction_op(s, a->rn, esz, 0, elts, fpst,
+                                       s->fpcr_ah ? fah : fnormal);
         write_fp_sreg(s, a->rd, res);
     }
     return true;
 }
 
-TRANS_FEAT(FMAXNMV_h, aa64_fp16, do_fp_reduction, a, gen_helper_vfp_maxnumh)
-TRANS_FEAT(FMINNMV_h, aa64_fp16, do_fp_reduction, a, gen_helper_vfp_minnumh)
-TRANS_FEAT(FMAXV_h, aa64_fp16, do_fp_reduction, a, gen_helper_vfp_maxh)
-TRANS_FEAT(FMINV_h, aa64_fp16, do_fp_reduction, a, gen_helper_vfp_minh)
+TRANS_FEAT(FMAXNMV_h, aa64_fp16, do_fp_reduction, a,
+           gen_helper_vfp_maxnumh, gen_helper_vfp_maxnumh)
+TRANS_FEAT(FMINNMV_h, aa64_fp16, do_fp_reduction, a,
+           gen_helper_vfp_minnumh, gen_helper_vfp_minnumh)
+TRANS_FEAT(FMAXV_h, aa64_fp16, do_fp_reduction, a,
+           gen_helper_vfp_maxh, gen_helper_vfp_ah_maxh)
+TRANS_FEAT(FMINV_h, aa64_fp16, do_fp_reduction, a,
+           gen_helper_vfp_minh, gen_helper_vfp_ah_minh)
 
-TRANS(FMAXNMV_s, do_fp_reduction, a, gen_helper_vfp_maxnums)
-TRANS(FMINNMV_s, do_fp_reduction, a, gen_helper_vfp_minnums)
-TRANS(FMAXV_s, do_fp_reduction, a, gen_helper_vfp_maxs)
-TRANS(FMINV_s, do_fp_reduction, a, gen_helper_vfp_mins)
+TRANS(FMAXNMV_s, do_fp_reduction, a,
+      gen_helper_vfp_maxnums, gen_helper_vfp_maxnums)
+TRANS(FMINNMV_s, do_fp_reduction, a,
+      gen_helper_vfp_minnums, gen_helper_vfp_minnums)
+TRANS(FMAXV_s, do_fp_reduction, a, gen_helper_vfp_maxs, gen_helper_vfp_ah_maxs)
+TRANS(FMINV_s, do_fp_reduction, a, gen_helper_vfp_mins, gen_helper_vfp_ah_mins)
 
 /*
  * Floating-point Immediate
-- 
2.34.1

Implement the FPCR.AH semantics for the pairwise floating
point minimum/maximum insns FMINP and FMAXP.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 ++++++++++++++
 target/arm/tcg/translate-a64.c | 25 +++++++++++++++++++++----
 target/arm/tcg/vec_helper.c    | 10 ++++++++++
 3 files changed, 45 insertions(+), 4 deletions(-)

Implement the FPCR.AH semantics for the SVE FMAXV and FMINV
vector-reduction-to-scalar max/min operations.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 +++++++++++
 target/arm/tcg/sve_helper.c    | 43 +++++++++++++++++++++-------------
 target/arm/tcg/translate-sve.c | 16 +++++++++++--
 3 files changed, 55 insertions(+), 18 deletions(-)

Implement the FPCR.AH semantics for the SVE FMAX and FMIN operations
that take an immediate as the second operand.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 ++++++++++++++
 target/arm/tcg/sve_helper.c    |  8 ++++++++
 target/arm/tcg/translate-sve.c | 25 +++++++++++++++++++++++--
 3 files changed, 45 insertions(+), 2 deletions(-)

Implement the FPCR.AH semantics for the SVE FMAX and FMIN
operations that take two vector operands.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 ++++++++++++++
 target/arm/tcg/sve_helper.c    |  8 ++++++++
 target/arm/tcg/translate-sve.c | 17 +++++++++++++++--
 3 files changed, 37 insertions(+), 2 deletions(-)

FPCR.AH == 1 mandates that negation of a NaN value should not flip
its sign bit.  This means we can no longer use gen_vfp_neg*()
everywhere but must instead generate slightly more complex code when
FPCR.AH is set.

Make this change for the scalar FNEG and for those places in
translate-a64.c which were previously directly calling
gen_vfp_neg*().

This change in semantics also affects any other instruction whose
pseudocode calls FPNeg(); in following commits we extend this
change to the other affected instructions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 125 ++++++++++++++++++++++++++++++---
 1 file changed, 114 insertions(+), 11 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void gen_gvec_op4_fpst(DisasContext *s, bool is_q, int rd, int rn,
                        is_q ? 16 : 8, vec_full_reg_size(s), data, fn);
 }
 
+/*
+ * When FPCR.AH == 1, NEG and ABS do not flip the sign bit of a NaN.
+ * These functions implement
+ *   d = floatN_is_any_nan(s) ? s : floatN_chs(s)
+ * which for float32 is
+ *   d = (s & ~(1 << 31)) > 0x7f800000UL) ? s : (s ^ (1 << 31))
+ * and similarly for the other float sizes.
+ */
+static void gen_vfp_ah_negh(TCGv_i32 d, TCGv_i32 s)
+{
+    TCGv_i32 abs_s = tcg_temp_new_i32(), chs_s = tcg_temp_new_i32();
+
+    gen_vfp_negh(chs_s, s);
+    gen_vfp_absh(abs_s, s);
+    tcg_gen_movcond_i32(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i32(0x7c00),
+                        s, chs_s);
+}
+
+static void gen_vfp_ah_negs(TCGv_i32 d, TCGv_i32 s)
+{
+    TCGv_i32 abs_s = tcg_temp_new_i32(), chs_s = tcg_temp_new_i32();
+
+    gen_vfp_negs(chs_s, s);
+    gen_vfp_abss(abs_s, s);
+    tcg_gen_movcond_i32(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i32(0x7f800000UL),
+                        s, chs_s);
+}
+
+static void gen_vfp_ah_negd(TCGv_i64 d, TCGv_i64 s)
+{
+    TCGv_i64 abs_s = tcg_temp_new_i64(), chs_s = tcg_temp_new_i64();
+
+    gen_vfp_negd(chs_s, s);
+    gen_vfp_absd(abs_s, s);
+    tcg_gen_movcond_i64(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i64(0x7ff0000000000000ULL),
+                        s, chs_s);
+}
+
+static void gen_vfp_maybe_ah_negh(DisasContext *dc, TCGv_i32 d, TCGv_i32 s)
+{
+    if (dc->fpcr_ah) {
+        gen_vfp_ah_negh(d, s);
+    } else {
+        gen_vfp_negh(d, s);
+    }
+}
+
+static void gen_vfp_maybe_ah_negs(DisasContext *dc, TCGv_i32 d, TCGv_i32 s)
+{
+    if (dc->fpcr_ah) {
+        gen_vfp_ah_negs(d, s);
+    } else {
+        gen_vfp_negs(d, s);
+    }
+}
+
+static void gen_vfp_maybe_ah_negd(DisasContext *dc, TCGv_i64 d, TCGv_i64 s)
+{
+    if (dc->fpcr_ah) {
+        gen_vfp_ah_negd(d, s);
+    } else {
+        gen_vfp_negd(d, s);
+    }
+}
+
 /* Set ZF and NF based on a 64 bit result. This is alas fiddlier
  * than the 32 bit equivalent.
  */
@@ -XXX,XX +XXX,XX @@ static void gen_fnmul_d(TCGv_i64 d, TCGv_i64 n, TCGv_i64 m, TCGv_ptr s)
     gen_vfp_negd(d, d);
 }
 
+static void gen_fnmul_ah_h(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
+{
+    gen_helper_vfp_mulh(d, n, m, s);
+    gen_vfp_ah_negh(d, d);
+}
+
+static void gen_fnmul_ah_s(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
+{
+    gen_helper_vfp_muls(d, n, m, s);
+    gen_vfp_ah_negs(d, d);
+}
+
+static void gen_fnmul_ah_d(TCGv_i64 d, TCGv_i64 n, TCGv_i64 m, TCGv_ptr s)
+{
+    gen_helper_vfp_muld(d, n, m, s);
+    gen_vfp_ah_negd(d, d);
+}
+
 static const FPScalar f_scalar_fnmul = {
     gen_fnmul_h,
     gen_fnmul_s,
     gen_fnmul_d,
 };
-TRANS(FNMUL_s, do_fp3_scalar, a, &f_scalar_fnmul, a->rn)
+static const FPScalar f_scalar_ah_fnmul = {
+    gen_fnmul_ah_h,
+    gen_fnmul_ah_s,
+    gen_fnmul_ah_d,
+};
+TRANS(FNMUL_s, do_fp3_scalar_2fn, a, &f_scalar_fnmul, &f_scalar_ah_fnmul, a->rn)
 
 static const FPScalar f_scalar_fcmeq = {
     gen_helper_advsimd_ceq_f16,
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
 
             read_vec_element(s, t2, a->rm, a->idx, MO_64);
             if (neg) {
-                gen_vfp_negd(t1, t1);
+                gen_vfp_maybe_ah_negd(s, t1, t1);
             }
             gen_helper_vfp_muladdd(t0, t1, t2, t0, fpstatus_ptr(FPST_A64));
             write_fp_dreg_merging(s, a->rd, a->rd, t0);
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
 
             read_vec_element_i32(s, t2, a->rm, a->idx, MO_32);
             if (neg) {
-                gen_vfp_negs(t1, t1);
+                gen_vfp_maybe_ah_negs(s, t1, t1);
             }
             gen_helper_vfp_muladds(t0, t1, t2, t0, fpstatus_ptr(FPST_A64));
             write_fp_sreg_merging(s, a->rd, a->rd, t0);
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_scalar_idx(DisasContext *s, arg_rrx_e *a, bool neg)
 
             read_vec_element_i32(s, t2, a->rm, a->idx, MO_16);
             if (neg) {
-                gen_vfp_negh(t1, t1);
+                gen_vfp_maybe_ah_negh(s, t1, t1);
             }
             gen_helper_advsimd_muladdh(t0, t1, t2, t0,
                                        fpstatus_ptr(FPST_A64_F16));
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             TCGv_i64 ta = read_fp_dreg(s, a->ra);
 
             if (neg_a) {
-                gen_vfp_negd(ta, ta);
+                gen_vfp_maybe_ah_negd(s, ta, ta);
             }
             if (neg_n) {
-                gen_vfp_negd(tn, tn);
+                gen_vfp_maybe_ah_negd(s, tn, tn);
             }
             fpst = fpstatus_ptr(FPST_A64);
             gen_helper_vfp_muladdd(ta, tn, tm, ta, fpst);
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             TCGv_i32 ta = read_fp_sreg(s, a->ra);
 
             if (neg_a) {
-                gen_vfp_negs(ta, ta);
+                gen_vfp_maybe_ah_negs(s, ta, ta);
             }
             if (neg_n) {
-                gen_vfp_negs(tn, tn);
+                gen_vfp_maybe_ah_negs(s, tn, tn);
             }
             fpst = fpstatus_ptr(FPST_A64);
             gen_helper_vfp_muladds(ta, tn, tm, ta, fpst);
@@ -XXX,XX +XXX,XX @@ static bool do_fmadd(DisasContext *s, arg_rrrr_e *a, bool neg_a, bool neg_n)
             TCGv_i32 ta = read_fp_hreg(s, a->ra);
 
             if (neg_a) {
-                gen_vfp_negh(ta, ta);
+                gen_vfp_maybe_ah_negh(s, ta, ta);
             }
             if (neg_n) {
-                gen_vfp_negh(tn, tn);
+                gen_vfp_maybe_ah_negh(s, tn, tn);
             }
             fpst = fpstatus_ptr(FPST_A64_F16);
             gen_helper_advsimd_muladdh(ta, tn, tm, ta, fpst);
@@ -XXX,XX +XXX,XX @@ static bool do_fp1_scalar_int(DisasContext *s, arg_rr_e *a,
     return true;
 }
 
+static bool do_fp1_scalar_int_2fn(DisasContext *s, arg_rr_e *a,
+                                  const FPScalar1Int *fnormal,
+                                  const FPScalar1Int *fah)
+{
+    return do_fp1_scalar_int(s, a, s->fpcr_ah ? fah : fnormal, true);
+}
+
 static const FPScalar1Int f_scalar_fmov = {
     tcg_gen_mov_i32,
     tcg_gen_mov_i32,
@@ -XXX,XX +XXX,XX @@ static const FPScalar1Int f_scalar_fneg = {
     gen_vfp_negs,
     gen_vfp_negd,
 };
-TRANS(FNEG_s, do_fp1_scalar_int, a, &f_scalar_fneg, true)
+static const FPScalar1Int f_scalar_ah_fneg = {
+    gen_vfp_ah_negh,
+    gen_vfp_ah_negs,
+    gen_vfp_ah_negd,
+};
+TRANS(FNEG_s, do_fp1_scalar_int_2fn, a, &f_scalar_fneg, &f_scalar_ah_fneg)
 
 typedef struct FPScalar1 {
     void (*gen_h)(TCGv_i32, TCGv_i32, TCGv_ptr);
-- 
2.34.1

FPCR.AH == 1 mandates that taking the absolute value of a NaN should
not change its sign bit.  This means we can no longer use
gen_vfp_abs*() everywhere but must instead generate slightly more
complex code when FPCR.AH is set.

Implement these semantics for scalar FABS and FABD.  This change also
affects all other instructions whose psuedocode calls FPAbs(); we
will extend the change to those instructions in following commits.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 69 +++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 2 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static void gen_vfp_ah_negd(TCGv_i64 d, TCGv_i64 s)
                         s, chs_s);
 }
 
+/*
+ * These functions implement
+ *  d = floatN_is_any_nan(s) ? s : floatN_abs(s)
+ * which for float32 is
+ *  d = (s & ~(1 << 31)) > 0x7f800000UL) ? s : (s & ~(1 << 31))
+ * and similarly for the other float sizes.
+ */
+static void gen_vfp_ah_absh(TCGv_i32 d, TCGv_i32 s)
+{
+    TCGv_i32 abs_s = tcg_temp_new_i32();
+
+    gen_vfp_absh(abs_s, s);
+    tcg_gen_movcond_i32(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i32(0x7c00),
+                        s, abs_s);
+}
+
+static void gen_vfp_ah_abss(TCGv_i32 d, TCGv_i32 s)
+{
+    TCGv_i32 abs_s = tcg_temp_new_i32();
+
+    gen_vfp_abss(abs_s, s);
+    tcg_gen_movcond_i32(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i32(0x7f800000UL),
+                        s, abs_s);
+}
+
+static void gen_vfp_ah_absd(TCGv_i64 d, TCGv_i64 s)
+{
+    TCGv_i64 abs_s = tcg_temp_new_i64();
+
+    gen_vfp_absd(abs_s, s);
+    tcg_gen_movcond_i64(TCG_COND_GTU, d,
+                        abs_s, tcg_constant_i64(0x7ff0000000000000ULL),
+                        s, abs_s);
+}
+
 static void gen_vfp_maybe_ah_negh(DisasContext *dc, TCGv_i32 d, TCGv_i32 s)
 {
     if (dc->fpcr_ah) {
@@ -XXX,XX +XXX,XX @@ static void gen_fabd_d(TCGv_i64 d, TCGv_i64 n, TCGv_i64 m, TCGv_ptr s)
     gen_vfp_absd(d, d);
 }
 
+static void gen_fabd_ah_h(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
+{
+    gen_helper_vfp_subh(d, n, m, s);
+    gen_vfp_ah_absh(d, d);
+}
+
+static void gen_fabd_ah_s(TCGv_i32 d, TCGv_i32 n, TCGv_i32 m, TCGv_ptr s)
+{
+    gen_helper_vfp_subs(d, n, m, s);
+    gen_vfp_ah_abss(d, d);
+}
+
+static void gen_fabd_ah_d(TCGv_i64 d, TCGv_i64 n, TCGv_i64 m, TCGv_ptr s)
+{
+    gen_helper_vfp_subd(d, n, m, s);
+    gen_vfp_ah_absd(d, d);
+}
+
 static const FPScalar f_scalar_fabd = {
     gen_fabd_h,
     gen_fabd_s,
     gen_fabd_d,
 };
-TRANS(FABD_s, do_fp3_scalar, a, &f_scalar_fabd, a->rn)
+static const FPScalar f_scalar_ah_fabd = {
+    gen_fabd_ah_h,
+    gen_fabd_ah_s,
+    gen_fabd_ah_d,
+};
+TRANS(FABD_s, do_fp3_scalar_2fn, a, &f_scalar_fabd, &f_scalar_ah_fabd, a->rn)
 
 static const FPScalar f_scalar_frecps = {
     gen_helper_recpsf_f16,
@@ -XXX,XX +XXX,XX @@ static const FPScalar1Int f_scalar_fabs = {
     gen_vfp_abss,
     gen_vfp_absd,
 };
-TRANS(FABS_s, do_fp1_scalar_int, a, &f_scalar_fabs, true)
+static const FPScalar1Int f_scalar_ah_fabs = {
+    gen_vfp_ah_absh,
+    gen_vfp_ah_abss,
+    gen_vfp_ah_absd,
+};
+TRANS(FABS_s, do_fp1_scalar_int_2fn, a, &f_scalar_fabs, &f_scalar_ah_fabs)
 
 static const FPScalar1Int f_scalar_fneg = {
     gen_vfp_negh,
-- 
2.34.1

Split the handling of vector FABD so that it calls a different set
of helpers when FPCR.AH is 1, which implement the "no negation of
the sign of a NaN" semantics.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/helper.h            |  4 ++++
 target/arm/tcg/translate-a64.c |  7 ++++++-
 target/arm/tcg/vec_helper.c    | 23 +++++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

Make SVE FNEG honour the FPCR.AH "don't negate the sign of a NaN"
semantics.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 4 ++++
 target/arm/tcg/sve_helper.c    | 8 ++++++++
 target/arm/tcg/translate-sve.c | 7 ++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

Make SVE FABS honour the FPCR.AH "don't negate the sign of a NaN"
semantics.

Make the SVE FABD insn honour the FPCR.AH "don't negate the sign
of a NaN" semantics.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    |  7 +++++++
 target/arm/tcg/sve_helper.c    | 22 ++++++++++++++++++++++
 target/arm/tcg/translate-sve.c |  2 +-
 3 files changed, 30 insertions(+), 1 deletion(-)

The negation steps in FCADD must honour FPCR.AH's "don't change the
sign of a NaN" semantics.  Implement this in the same way we did for
the base ASIMD FCADD, by encoding FPCR.AH into the SIMD data field
passed to the helper and using that to decide whether to negate the
values.

The construction of neg_imag and neg_real were done to make it easy
to apply both in parallel with two simple logical operations.  This
changed with FPCR.AH, which is more complex than that. Switch to
an approach that follows the pseudocode more closely, by extracting
the 'rot=1' parameter from the SIMD data field and changing the
sign of the appropriate input value.

Note that there was a naming issue with neg_imag and neg_real.
They were named backward, with neg_imag being non-zero for rot=1,
and vice versa.  This was combined with reversed usage within the
loop, so that the negation in the end turned out correct.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/vec_internal.h  | 17 ++++++++++++++
 target/arm/tcg/sve_helper.c    | 42 ++++++++++++++++++++++++----------
 target/arm/tcg/translate-sve.c |  2 +-
 3 files changed, 48 insertions(+), 13 deletions(-)

diff --git a/target/arm/tcg/vec_internal.h b/target/arm/tcg/vec_internal.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_internal.h
+++ b/target/arm/tcg/vec_internal.h
@@ -XXX,XX +XXX,XX @@
 #ifndef TARGET_ARM_VEC_INTERNAL_H
 #define TARGET_ARM_VEC_INTERNAL_H
 
+#include "fpu/softfloat.h"
+
 /*
  * Note that vector data is stored in host-endian 64-bit chunks,
  * so addressing units smaller than that needs a host-endian fixup.
@@ -XXX,XX +XXX,XX @@ float32 bfdotadd_ebf(float32 sum, uint32_t e1, uint32_t e2,
  */
 bool is_ebf(CPUARMState *env, float_status *statusp, float_status *oddstatusp);
 
+static inline float16 float16_maybe_ah_chs(float16 a, bool fpcr_ah)
+{
+    return fpcr_ah && float16_is_any_nan(a) ? a : float16_chs(a);
+}
+
+static inline float32 float32_maybe_ah_chs(float32 a, bool fpcr_ah)
+{
+    return fpcr_ah && float32_is_any_nan(a) ? a : float32_chs(a);
+}
+
+static inline float64 float64_maybe_ah_chs(float64 a, bool fpcr_ah)
+{
+    return fpcr_ah && float64_is_any_nan(a) ? a : float64_chs(a);
+}
+
 #endif /* TARGET_ARM_VEC_INTERNAL_H */
diff --git a/target/arm/tcg/sve_helper.c b/target/arm/tcg/sve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/sve_helper.c
+++ b/target/arm/tcg/sve_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_h)(void *vd, void *vn, void *vm, void *vg,
 {
     intptr_t j, i = simd_oprsz(desc);
     uint64_t *g = vg;
-    float16 neg_imag = float16_set_sign(0, simd_data(desc));
-    float16 neg_real = float16_chs(neg_imag);
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_h)(void *vd, void *vn, void *vm, void *vg,
             i -= 2 * sizeof(float16);
 
             e0 = *(float16 *)(vn + H1_2(i));
-            e1 = *(float16 *)(vm + H1_2(j)) ^ neg_real;
+            e1 = *(float16 *)(vm + H1_2(j));
             e2 = *(float16 *)(vn + H1_2(j));
-            e3 = *(float16 *)(vm + H1_2(i)) ^ neg_imag;
+            e3 = *(float16 *)(vm + H1_2(i));
+
+            if (rot) {
+                e3 = float16_maybe_ah_chs(e3, fpcr_ah);
+            } else {
+                e1 = float16_maybe_ah_chs(e1, fpcr_ah);
+            }
 
             if (likely((pg >> (i & 63)) & 1)) {
                 *(float16 *)(vd + H1_2(i)) = float16_add(e0, e1, s);
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_s)(void *vd, void *vn, void *vm, void *vg,
 {
     intptr_t j, i = simd_oprsz(desc);
     uint64_t *g = vg;
-    float32 neg_imag = float32_set_sign(0, simd_data(desc));
-    float32 neg_real = float32_chs(neg_imag);
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_s)(void *vd, void *vn, void *vm, void *vg,
             i -= 2 * sizeof(float32);
 
             e0 = *(float32 *)(vn + H1_2(i));
-            e1 = *(float32 *)(vm + H1_2(j)) ^ neg_real;
+            e1 = *(float32 *)(vm + H1_2(j));
             e2 = *(float32 *)(vn + H1_2(j));
-            e3 = *(float32 *)(vm + H1_2(i)) ^ neg_imag;
+            e3 = *(float32 *)(vm + H1_2(i));
+
+            if (rot) {
+                e3 = float32_maybe_ah_chs(e3, fpcr_ah);
+            } else {
+                e1 = float32_maybe_ah_chs(e1, fpcr_ah);
+            }
 
             if (likely((pg >> (i & 63)) & 1)) {
                 *(float32 *)(vd + H1_2(i)) = float32_add(e0, e1, s);
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_d)(void *vd, void *vn, void *vm, void *vg,
 {
     intptr_t j, i = simd_oprsz(desc);
     uint64_t *g = vg;
-    float64 neg_imag = float64_set_sign(0, simd_data(desc));
-    float64 neg_real = float64_chs(neg_imag);
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcadd_d)(void *vd, void *vn, void *vm, void *vg,
             i -= 2 * sizeof(float64);
 
             e0 = *(float64 *)(vn + H1_2(i));
-            e1 = *(float64 *)(vm + H1_2(j)) ^ neg_real;
+            e1 = *(float64 *)(vm + H1_2(j));
             e2 = *(float64 *)(vn + H1_2(j));
-            e3 = *(float64 *)(vm + H1_2(i)) ^ neg_imag;
+            e3 = *(float64 *)(vm + H1_2(i));
+
+            if (rot) {
+                e3 = float64_maybe_ah_chs(e3, fpcr_ah);
+            } else {
+                e1 = float64_maybe_ah_chs(e1, fpcr_ah);
+            }
 
             if (likely((pg >> (i & 63)) & 1)) {
                 *(float64 *)(vd + H1_2(i)) = float64_add(e0, e1, s);
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_4_ptr * const fcadd_fns[] = {
     gen_helper_sve_fcadd_s, gen_helper_sve_fcadd_d,
 };
 TRANS_FEAT(FCADD, aa64_sve, gen_gvec_fpst_zzzp, fcadd_fns[a->esz],
-           a->rd, a->rn, a->rm, a->pg, a->rot,
+           a->rd, a->rn, a->rm, a->pg, a->rot | (s->fpcr_ah << 1),
            a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
 #define DO_FMLA(NAME, name) \
-- 
2.34.1

The negation steps in FCADD must honour FPCR.AH's "don't change the
sign of a NaN" semantics.  Implement this by encoding FPCR.AH into
the SIMD data field passed to the helper and using that to decide
whether to negate the values.

The construction of neg_imag and neg_real were done to make it easy
to apply both in parallel with two simple logical operations.  This
changed with FPCR.AH, which is more complex than that. Switch to
an approach closer to the pseudocode, where we extract the rot
parameter from the SIMD data word and negate the appropriate
input value.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 10 +++++--
 target/arm/tcg/vec_helper.c    | 54 +++++++++++++++++++---------------
 2 files changed, 38 insertions(+), 26 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_3_ptr * const f_vector_fcadd[3] = {
     gen_helper_gvec_fcadds,
     gen_helper_gvec_fcaddd,
 };
-TRANS_FEAT(FCADD_90, aa64_fcma, do_fp3_vector, a, 0, f_vector_fcadd)
-TRANS_FEAT(FCADD_270, aa64_fcma, do_fp3_vector, a, 1, f_vector_fcadd)
+/*
+ * Encode FPCR.AH into the data so the helper knows whether the
+ * negations it does should avoid flipping the sign bit on a NaN
+ */
+TRANS_FEAT(FCADD_90, aa64_fcma, do_fp3_vector, a, 0 | (s->fpcr_ah << 1),
+           f_vector_fcadd)
+TRANS_FEAT(FCADD_270, aa64_fcma, do_fp3_vector, a, 1 | (s->fpcr_ah << 1),
+           f_vector_fcadd)
 
 static bool trans_FCMLA_v(DisasContext *s, arg_FCMLA_v *a)
 {
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcaddh)(void *vd, void *vn, void *vm,
     float16 *d = vd;
     float16 *n = vn;
     float16 *m = vm;
-    uint32_t neg_real = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = neg_real ^ 1;
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 15;
-    neg_imag <<= 15;
-
     for (i = 0; i < opr_sz / 2; i += 2) {
         float16 e0 = n[H2(i)];
-        float16 e1 = m[H2(i + 1)] ^ neg_imag;
+        float16 e1 = m[H2(i + 1)];
         float16 e2 = n[H2(i + 1)];
-        float16 e3 = m[H2(i)] ^ neg_real;
+        float16 e3 = m[H2(i)];
+
+        if (rot) {
+            e3 = float16_maybe_ah_chs(e3, fpcr_ah);
+        } else {
+            e1 = float16_maybe_ah_chs(e1, fpcr_ah);
+        }
 
         d[H2(i)] = float16_add(e0, e1, fpst);
         d[H2(i + 1)] = float16_add(e2, e3, fpst);
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcadds)(void *vd, void *vn, void *vm,
     float32 *d = vd;
     float32 *n = vn;
     float32 *m = vm;
-    uint32_t neg_real = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = neg_real ^ 1;
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 31;
-    neg_imag <<= 31;
-
     for (i = 0; i < opr_sz / 4; i += 2) {
         float32 e0 = n[H4(i)];
-        float32 e1 = m[H4(i + 1)] ^ neg_imag;
+        float32 e1 = m[H4(i + 1)];
         float32 e2 = n[H4(i + 1)];
-        float32 e3 = m[H4(i)] ^ neg_real;
+        float32 e3 = m[H4(i)];
+
+        if (rot) {
+            e3 = float32_maybe_ah_chs(e3, fpcr_ah);
+        } else {
+            e1 = float32_maybe_ah_chs(e1, fpcr_ah);
+        }
 
         d[H4(i)] = float32_add(e0, e1, fpst);
         d[H4(i + 1)] = float32_add(e2, e3, fpst);
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcaddd)(void *vd, void *vn, void *vm,
     float64 *d = vd;
     float64 *n = vn;
     float64 *m = vm;
-    uint64_t neg_real = extract64(desc, SIMD_DATA_SHIFT, 1);
-    uint64_t neg_imag = neg_real ^ 1;
+    bool rot = extract32(desc, SIMD_DATA_SHIFT, 1);
+    bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 63;
-    neg_imag <<= 63;
-
     for (i = 0; i < opr_sz / 8; i += 2) {
         float64 e0 = n[i];
-        float64 e1 = m[i + 1] ^ neg_imag;
+        float64 e1 = m[i + 1];
         float64 e2 = n[i + 1];
-        float64 e3 = m[i] ^ neg_real;
+        float64 e3 = m[i];
+
+        if (rot) {
+            e3 = float64_maybe_ah_chs(e3, fpcr_ah);
+        } else {
+            e1 = float64_maybe_ah_chs(e1, fpcr_ah);
+        }
 
         d[i] = float64_add(e0, e1, fpst);
         d[i + 1] = float64_add(e2, e3, fpst);
-- 
2.34.1

Handle the FPCR.AH semantics that we do not change the sign of an
input NaN in the FRECPS and FRSQRTS scalar insns, by providing
new helper functions that do the CHS part of the operation
differently.

Since the extra helper functions would be very repetitive if written
out longhand, we condense them and the existing non-AH helpers into
being emitted via macros.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-a64.h    |   6 ++
 target/arm/tcg/vec_internal.h  |  18 ++++++
 target/arm/tcg/helper-a64.c    | 115 ++++++++++++---------------------
 target/arm/tcg/translate-a64.c |  25 +++++--
 4 files changed, 83 insertions(+), 81 deletions(-)

diff --git a/target/arm/tcg/helper-a64.h b/target/arm/tcg/helper-a64.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/helper-a64.h
+++ b/target/arm/tcg/helper-a64.h
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_FLAGS_3(neon_cgt_f64, TCG_CALL_NO_RWG, i64, i64, i64, fpst)
 DEF_HELPER_FLAGS_3(recpsf_f16, TCG_CALL_NO_RWG, f16, f16, f16, fpst)
 DEF_HELPER_FLAGS_3(recpsf_f32, TCG_CALL_NO_RWG, f32, f32, f32, fpst)
 DEF_HELPER_FLAGS_3(recpsf_f64, TCG_CALL_NO_RWG, f64, f64, f64, fpst)
+DEF_HELPER_FLAGS_3(recpsf_ah_f16, TCG_CALL_NO_RWG, f16, f16, f16, fpst)
+DEF_HELPER_FLAGS_3(recpsf_ah_f32, TCG_CALL_NO_RWG, f32, f32, f32, fpst)
+DEF_HELPER_FLAGS_3(recpsf_ah_f64, TCG_CALL_NO_RWG, f64, f64, f64, fpst)
 DEF_HELPER_FLAGS_3(rsqrtsf_f16, TCG_CALL_NO_RWG, f16, f16, f16, fpst)
 DEF_HELPER_FLAGS_3(rsqrtsf_f32, TCG_CALL_NO_RWG, f32, f32, f32, fpst)
 DEF_HELPER_FLAGS_3(rsqrtsf_f64, TCG_CALL_NO_RWG, f64, f64, f64, fpst)
+DEF_HELPER_FLAGS_3(rsqrtsf_ah_f16, TCG_CALL_NO_RWG, f16, f16, f16, fpst)
+DEF_HELPER_FLAGS_3(rsqrtsf_ah_f32, TCG_CALL_NO_RWG, f32, f32, f32, fpst)
+DEF_HELPER_FLAGS_3(rsqrtsf_ah_f64, TCG_CALL_NO_RWG, f64, f64, f64, fpst)
 DEF_HELPER_FLAGS_2(frecpx_f64, TCG_CALL_NO_RWG, f64, f64, fpst)
 DEF_HELPER_FLAGS_2(frecpx_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
 DEF_HELPER_FLAGS_2(frecpx_f16, TCG_CALL_NO_RWG, f16, f16, fpst)
diff --git a/target/arm/tcg/vec_internal.h b/target/arm/tcg/vec_internal.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_internal.h
+++ b/target/arm/tcg/vec_internal.h
@@ -XXX,XX +XXX,XX @@ float32 bfdotadd_ebf(float32 sum, uint32_t e1, uint32_t e2,
  */
 bool is_ebf(CPUARMState *env, float_status *statusp, float_status *oddstatusp);
 
+/*
+ * Negate as for FPCR.AH=1 -- do not negate NaNs.
+ */
+static inline float16 float16_ah_chs(float16 a)
+{
+    return float16_is_any_nan(a) ? a : float16_chs(a);
+}
+
+static inline float32 float32_ah_chs(float32 a)
+{
+    return float32_is_any_nan(a) ? a : float32_chs(a);
+}
+
+static inline float64 float64_ah_chs(float64 a)
+{
+    return float64_is_any_nan(a) ? a : float64_chs(a);
+}
+
 static inline float16 float16_maybe_ah_chs(float16 a, bool fpcr_ah)
 {
     return fpcr_ah && float16_is_any_nan(a) ? a : float16_chs(a);
diff --git a/target/arm/tcg/helper-a64.c b/target/arm/tcg/helper-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/helper-a64.c
+++ b/target/arm/tcg/helper-a64.c
@@ -XXX,XX +XXX,XX @@
 #ifdef CONFIG_USER_ONLY
 #include "user/page-protection.h"
 #endif
+#include "vec_internal.h"
 
 /* C2.4.7 Multiply and divide */
 /* special cases for 0 and LLONG_MIN are mandated by the standard */
@@ -XXX,XX +XXX,XX @@ uint64_t HELPER(neon_cgt_f64)(float64 a, float64 b, float_status *fpst)
     return -float64_lt(b, a, fpst);
 }
 
-/* Reciprocal step and sqrt step. Note that unlike the A32/T32
+/*
+ * Reciprocal step and sqrt step. Note that unlike the A32/T32
  * versions, these do a fully fused multiply-add or
  * multiply-add-and-halve.
+ * The FPCR.AH == 1 versions need to avoid flipping the sign of NaN.
  */
-
-uint32_t HELPER(recpsf_f16)(uint32_t a, uint32_t b, float_status *fpst)
-{
-    a = float16_squash_input_denormal(a, fpst);
-    b = float16_squash_input_denormal(b, fpst);
-
-    a = float16_chs(a);
-    if ((float16_is_infinity(a) && float16_is_zero(b)) ||
-        (float16_is_infinity(b) && float16_is_zero(a))) {
-        return float16_two;
+#define DO_RECPS(NAME, CTYPE, FLOATTYPE, CHSFN)                         \
+    CTYPE HELPER(NAME)(CTYPE a, CTYPE b, float_status *fpst)            \
+    {                                                                   \
+        a = FLOATTYPE ## _squash_input_denormal(a, fpst);               \
+        b = FLOATTYPE ## _squash_input_denormal(b, fpst);               \
+        a = FLOATTYPE ## _ ## CHSFN(a);                                 \
+        if ((FLOATTYPE ## _is_infinity(a) && FLOATTYPE ## _is_zero(b)) || \
+            (FLOATTYPE ## _is_infinity(b) && FLOATTYPE ## _is_zero(a))) { \
+            return FLOATTYPE ## _two;                                   \
+        }                                                               \
+        return FLOATTYPE ## _muladd(a, b, FLOATTYPE ## _two, 0, fpst);  \
     }
-    return float16_muladd(a, b, float16_two, 0, fpst);
-}
 
-float32 HELPER(recpsf_f32)(float32 a, float32 b, float_status *fpst)
-{
-    a = float32_squash_input_denormal(a, fpst);
-    b = float32_squash_input_denormal(b, fpst);
+DO_RECPS(recpsf_f16, uint32_t, float16, chs)
+DO_RECPS(recpsf_f32, float32, float32, chs)
+DO_RECPS(recpsf_f64, float64, float64, chs)
+DO_RECPS(recpsf_ah_f16, uint32_t, float16, ah_chs)
+DO_RECPS(recpsf_ah_f32, float32, float32, ah_chs)
+DO_RECPS(recpsf_ah_f64, float64, float64, ah_chs)
 
-    a = float32_chs(a);
-    if ((float32_is_infinity(a) && float32_is_zero(b)) ||
-        (float32_is_infinity(b) && float32_is_zero(a))) {
-        return float32_two;
-    }
-    return float32_muladd(a, b, float32_two, 0, fpst);
-}
+#define DO_RSQRTSF(NAME, CTYPE, FLOATTYPE, CHSFN)                       \
+    CTYPE HELPER(NAME)(CTYPE a, CTYPE b, float_status *fpst)            \
+    {                                                                   \
+        a = FLOATTYPE ## _squash_input_denormal(a, fpst);               \
+        b = FLOATTYPE ## _squash_input_denormal(b, fpst);               \
+        a = FLOATTYPE ## _ ## CHSFN(a);                                 \
+        if ((FLOATTYPE ## _is_infinity(a) && FLOATTYPE ## _is_zero(b)) || \
+            (FLOATTYPE ## _is_infinity(b) && FLOATTYPE ## _is_zero(a))) { \
+            return FLOATTYPE ## _one_point_five;                        \
+        }                                                               \
+        return FLOATTYPE ## _muladd_scalbn(a, b, FLOATTYPE ## _three,   \
+                                           -1, 0, fpst);                \
+    }                                                                   \
 
-float64 HELPER(recpsf_f64)(float64 a, float64 b, float_status *fpst)
-{
-    a = float64_squash_input_denormal(a, fpst);
-    b = float64_squash_input_denormal(b, fpst);
-
-    a = float64_chs(a);
-    if ((float64_is_infinity(a) && float64_is_zero(b)) ||
-        (float64_is_infinity(b) && float64_is_zero(a))) {
-        return float64_two;
-    }
-    return float64_muladd(a, b, float64_two, 0, fpst);
-}
-
-uint32_t HELPER(rsqrtsf_f16)(uint32_t a, uint32_t b, float_status *fpst)
-{
-    a = float16_squash_input_denormal(a, fpst);
-    b = float16_squash_input_denormal(b, fpst);
-
-    a = float16_chs(a);
-    if ((float16_is_infinity(a) && float16_is_zero(b)) ||
-        (float16_is_infinity(b) && float16_is_zero(a))) {
-        return float16_one_point_five;
-    }
-    return float16_muladd_scalbn(a, b, float16_three, -1, 0, fpst);
-}
-
-float32 HELPER(rsqrtsf_f32)(float32 a, float32 b, float_status *fpst)
-{
-    a = float32_squash_input_denormal(a, fpst);
-    b = float32_squash_input_denormal(b, fpst);
-
-    a = float32_chs(a);
-    if ((float32_is_infinity(a) && float32_is_zero(b)) ||
-        (float32_is_infinity(b) && float32_is_zero(a))) {
-        return float32_one_point_five;
-    }
-    return float32_muladd_scalbn(a, b, float32_three, -1, 0, fpst);
-}
-
-float64 HELPER(rsqrtsf_f64)(float64 a, float64 b, float_status *fpst)
-{
-    a = float64_squash_input_denormal(a, fpst);
-    b = float64_squash_input_denormal(b, fpst);
-
-    a = float64_chs(a);
-    if ((float64_is_infinity(a) && float64_is_zero(b)) ||
-        (float64_is_infinity(b) && float64_is_zero(a))) {
-        return float64_one_point_five;
-    }
-    return float64_muladd_scalbn(a, b, float64_three, -1, 0, fpst);
-}
+DO_RSQRTSF(rsqrtsf_f16, uint32_t, float16, chs)
+DO_RSQRTSF(rsqrtsf_f32, float32, float32, chs)
+DO_RSQRTSF(rsqrtsf_f64, float64, float64, chs)
+DO_RSQRTSF(rsqrtsf_ah_f16, uint32_t, float16, ah_chs)
+DO_RSQRTSF(rsqrtsf_ah_f32, float32, float32, ah_chs)
+DO_RSQRTSF(rsqrtsf_ah_f64, float64, float64, ah_chs)
 
 /* Floating-point reciprocal exponent - see FPRecpX in ARM ARM */
 uint32_t HELPER(frecpx_f16)(uint32_t a, float_status *fpst)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool do_fp3_scalar(DisasContext *s, arg_rrr_e *a, const FPScalar *f,
                                        FPST_A64_F16 : FPST_A64);
 }
 
-static bool do_fp3_scalar_ah(DisasContext *s, arg_rrr_e *a, const FPScalar *f,
-                             int mergereg)
+static bool do_fp3_scalar_ah_2fn(DisasContext *s, arg_rrr_e *a,
+                                 const FPScalar *fnormal, const FPScalar *fah,
+                                 int mergereg)
 {
-    return do_fp3_scalar_with_fpsttype(s, a, f, mergereg,
-                                       select_ah_fpst(s, a->esz));
+    return do_fp3_scalar_with_fpsttype(s, a, s->fpcr_ah ? fah : fnormal,
+                                       mergereg, select_ah_fpst(s, a->esz));
 }
 
 /* Some insns need to call different helpers when FPCR.AH == 1 */
@@ -XXX,XX +XXX,XX @@ static const FPScalar f_scalar_frecps = {
     gen_helper_recpsf_f32,
     gen_helper_recpsf_f64,
 };
-TRANS(FRECPS_s, do_fp3_scalar_ah, a, &f_scalar_frecps, a->rn)
+static const FPScalar f_scalar_ah_frecps = {
+    gen_helper_recpsf_ah_f16,
+    gen_helper_recpsf_ah_f32,
+    gen_helper_recpsf_ah_f64,
+};
+TRANS(FRECPS_s, do_fp3_scalar_ah_2fn, a,
+      &f_scalar_frecps, &f_scalar_ah_frecps, a->rn)
 
 static const FPScalar f_scalar_frsqrts = {
     gen_helper_rsqrtsf_f16,
     gen_helper_rsqrtsf_f32,
     gen_helper_rsqrtsf_f64,
 };
-TRANS(FRSQRTS_s, do_fp3_scalar_ah, a, &f_scalar_frsqrts, a->rn)
+static const FPScalar f_scalar_ah_frsqrts = {
+    gen_helper_rsqrtsf_ah_f16,
+    gen_helper_rsqrtsf_ah_f32,
+    gen_helper_rsqrtsf_ah_f64,
+};
+TRANS(FRSQRTS_s, do_fp3_scalar_ah_2fn, a,
+      &f_scalar_frsqrts, &f_scalar_ah_frsqrts, a->rn)
 
 static bool do_fcmp0_s(DisasContext *s, arg_rr_e *a,
                        const FPScalar *f, bool swap)
-- 
2.34.1

Handle the FPCR.AH "don't negate the sign of a NaN" semantics
in the vector versions of FRECPS and FRSQRTS, by implementing
new vector wrappers that call the _ah_ scalar helpers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 14 ++++++++++++++
 target/arm/tcg/translate-a64.c | 21 ++++++++++++++++-----
 target/arm/tcg/translate-sve.c |  7 ++++++-
 target/arm/tcg/vec_helper.c    |  8 ++++++++
 4 files changed, 44 insertions(+), 6 deletions(-)

Handle the FPCR.AH "don't negate the sign of a NaN" semantics in FMLS
(indexed). We do this by creating 6 new helpers, which allow us to
do the negation either by XOR (for AH=0) or by muladd flags
(for AH=1).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: Mostly from RTH's patch; error in index order into fns[][]
 fixed]
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/helper.h            | 14 ++++++++++++++
 target/arm/tcg/translate-a64.c | 17 +++++++++++------
 target/arm/tcg/translate-sve.c | 31 +++++++++++++++++--------------
 target/arm/tcg/vec_helper.c    | 24 +++++++++++++++---------
 4 files changed, 57 insertions(+), 29 deletions(-)

diff --git a/target/arm/helper.h b/target/arm/helper.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_FLAGS_6(gvec_fmla_idx_s, TCG_CALL_NO_RWG,
 DEF_HELPER_FLAGS_6(gvec_fmla_idx_d, TCG_CALL_NO_RWG,
                    void, ptr, ptr, ptr, ptr, fpst, i32)
 
+DEF_HELPER_FLAGS_6(gvec_fmls_idx_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_6(gvec_fmls_idx_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_6(gvec_fmls_idx_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+
+DEF_HELPER_FLAGS_6(gvec_ah_fmls_idx_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_6(gvec_ah_fmls_idx_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_6(gvec_ah_fmls_idx_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, fpst, i32)
+
 DEF_HELPER_FLAGS_5(gvec_uqadd_b, TCG_CALL_NO_RWG,
                    void, ptr, ptr, ptr, ptr, i32)
 DEF_HELPER_FLAGS_5(gvec_uqadd_h, TCG_CALL_NO_RWG,
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ TRANS(FMULX_vi, do_fp3_vector_idx, a, f_vector_idx_fmulx)
 
 static bool do_fmla_vector_idx(DisasContext *s, arg_qrrx_e *a, bool neg)
 {
-    static gen_helper_gvec_4_ptr * const fns[3] = {
-        gen_helper_gvec_fmla_idx_h,
-        gen_helper_gvec_fmla_idx_s,
-        gen_helper_gvec_fmla_idx_d,
+    static gen_helper_gvec_4_ptr * const fns[3][3] = {
+        { gen_helper_gvec_fmla_idx_h,
+          gen_helper_gvec_fmla_idx_s,
+          gen_helper_gvec_fmla_idx_d },
+        { gen_helper_gvec_fmls_idx_h,
+          gen_helper_gvec_fmls_idx_s,
+          gen_helper_gvec_fmls_idx_d },
+        { gen_helper_gvec_ah_fmls_idx_h,
+          gen_helper_gvec_ah_fmls_idx_s,
+          gen_helper_gvec_ah_fmls_idx_d },
     };
     MemOp esz = a->esz;
     int check = fp_access_check_vector_hsd(s, a->q, esz);
@@ -XXX,XX +XXX,XX @@ static bool do_fmla_vector_idx(DisasContext *s, arg_qrrx_e *a, bool neg)
 
     gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
                       esz == MO_16 ? FPST_A64_F16 : FPST_A64,
-                      (a->idx << 1) | neg,
-                      fns[esz - 1]);
+                      a->idx, fns[neg ? 1 + s->fpcr_ah : 0][esz - 1]);
     return true;
 }
 
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ DO_SVE2_RRXR_ROT(CDOT_zzxw_d, gen_helper_sve2_cdot_idx_d)
  *** SVE Floating Point Multiply-Add Indexed Group
  */
 
-static bool do_FMLA_zzxz(DisasContext *s, arg_rrxr_esz *a, bool sub)
-{
-    static gen_helper_gvec_4_ptr * const fns[4] = {
-        NULL,
-        gen_helper_gvec_fmla_idx_h,
-        gen_helper_gvec_fmla_idx_s,
-        gen_helper_gvec_fmla_idx_d,
-    };
-    return gen_gvec_fpst_zzzz(s, fns[a->esz], a->rd, a->rn, a->rm, a->ra,
-                              (a->index << 1) | sub,
-                              a->esz == MO_16 ? FPST_A64_F16 : FPST_A64);
-}
+static gen_helper_gvec_4_ptr * const fmla_idx_fns[4] = {
+    NULL,                       gen_helper_gvec_fmla_idx_h,
+    gen_helper_gvec_fmla_idx_s, gen_helper_gvec_fmla_idx_d
+};
+TRANS_FEAT(FMLA_zzxz, aa64_sve, gen_gvec_fpst_zzzz,
+           fmla_idx_fns[a->esz], a->rd, a->rn, a->rm, a->ra, a->index,
+           a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
-TRANS_FEAT(FMLA_zzxz, aa64_sve, do_FMLA_zzxz, a, false)
-TRANS_FEAT(FMLS_zzxz, aa64_sve, do_FMLA_zzxz, a, true)
+static gen_helper_gvec_4_ptr * const fmls_idx_fns[4][2] = {
+    { NULL, NULL },
+    { gen_helper_gvec_fmls_idx_h, gen_helper_gvec_ah_fmls_idx_h },
+    { gen_helper_gvec_fmls_idx_s, gen_helper_gvec_ah_fmls_idx_s },
+    { gen_helper_gvec_fmls_idx_d, gen_helper_gvec_ah_fmls_idx_d },
+};
+TRANS_FEAT(FMLS_zzxz, aa64_sve, gen_gvec_fpst_zzzz,
+           fmls_idx_fns[a->esz][s->fpcr_ah],
+           a->rd, a->rn, a->rm, a->ra, a->index,
+           a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
 /*
  *** SVE Floating Point Multiply Indexed Group
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ DO_FMUL_IDX(gvec_fmls_nf_idx_s, float32_sub, float32_mul, float32, H4)
 
 #undef DO_FMUL_IDX
 
-#define DO_FMLA_IDX(NAME, TYPE, H)                                         \
+#define DO_FMLA_IDX(NAME, TYPE, H, NEGX, NEGF)                             \
 void HELPER(NAME)(void *vd, void *vn, void *vm, void *va,                  \
                   float_status *stat, uint32_t desc)                       \
 {                                                                          \
     intptr_t i, j, oprsz = simd_oprsz(desc);                               \
     intptr_t segment = MIN(16, oprsz) / sizeof(TYPE);                      \
-    TYPE op1_neg = extract32(desc, SIMD_DATA_SHIFT, 1);                    \
-    intptr_t idx = desc >> (SIMD_DATA_SHIFT + 1);                          \
+    intptr_t idx = simd_data(desc);                                        \
     TYPE *d = vd, *n = vn, *m = vm, *a = va;                               \
-    op1_neg <<= (8 * sizeof(TYPE) - 1);                                    \
     for (i = 0; i < oprsz / sizeof(TYPE); i += segment) {                  \
         TYPE mm = m[H(i + idx)];                                           \
         for (j = 0; j < segment; j++) {                                    \
-            d[i + j] = TYPE##_muladd(n[i + j] ^ op1_neg,                   \
-                                     mm, a[i + j], 0, stat);               \
+            d[i + j] = TYPE##_muladd(n[i + j] ^ NEGX, mm,                  \
+                                     a[i + j], NEGF, stat);                \
         }                                                                  \
     }                                                                      \
     clear_tail(d, oprsz, simd_maxsz(desc));                                \
 }
 
-DO_FMLA_IDX(gvec_fmla_idx_h, float16, H2)
-DO_FMLA_IDX(gvec_fmla_idx_s, float32, H4)
-DO_FMLA_IDX(gvec_fmla_idx_d, float64, H8)
+DO_FMLA_IDX(gvec_fmla_idx_h, float16, H2, 0, 0)
+DO_FMLA_IDX(gvec_fmla_idx_s, float32, H4, 0, 0)
+DO_FMLA_IDX(gvec_fmla_idx_d, float64, H8, 0, 0)
+
+DO_FMLA_IDX(gvec_fmls_idx_h, float16, H2, INT16_MIN, 0)
+DO_FMLA_IDX(gvec_fmls_idx_s, float32, H4, INT32_MIN, 0)
+DO_FMLA_IDX(gvec_fmls_idx_d, float64, H8, INT64_MIN, 0)
+
+DO_FMLA_IDX(gvec_ah_fmls_idx_h, float16, H2, 0, float_muladd_negate_product)
+DO_FMLA_IDX(gvec_ah_fmls_idx_s, float32, H4, 0, float_muladd_negate_product)
+DO_FMLA_IDX(gvec_ah_fmls_idx_d, float64, H8, 0, float_muladd_negate_product)
 
 #undef DO_FMLA_IDX
 
-- 
2.34.1

Handle the FPCR.AH "don't negate the sign of a NaN" semantics
in FMLS (vector), by implementing a new set of helpers for
the AH=1 case.

The float_muladd_negate_product flag produces the same result
as negating either of the multiplication operands, assuming
neither of the operands are NaNs.  But since FEAT_AFP does not
negate NaNs, this behaviour is exactly what we need.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/helper.h            |  4 ++++
 target/arm/tcg/translate-a64.c |  7 ++++++-
 target/arm/tcg/vec_helper.c    | 22 ++++++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

Handle the FPCR.AH "don't negate the sign of a NaN" semantics fro the
SVE FMLS (vector) insns, by providing new helpers for the AH=1 case
which end up passing fpcr_ah = true to the do_fmla_zpzzz_* functions
that do the work.

The float*_muladd functions have a flags argument that can
perform optional negation of various operand.  We don't use
that for "normal" arm fmla, because the muladd flags are not
applied when an input is a NaN.  But since FEAT_AFP does not
negate NaNs, this behaviour is exactly what we need.

The non-AH helpers pass in a zero flags argument and control the
negation via the neg1 and neg3 arguments; the AH helpers always pass
in neg1 and neg3 as zero and control the negation via the flags
argument.  This allows us to avoid conditional branches within the
inner loop.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/helper-sve.h    | 21 ++++++++
 target/arm/tcg/sve_helper.c    | 99 +++++++++++++++++++++++++++-------
 target/arm/tcg/translate-sve.c | 18 ++++---
 3 files changed, 114 insertions(+), 24 deletions(-)

diff --git a/target/arm/tcg/helper-sve.h b/target/arm/tcg/helper-sve.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/helper-sve.h
+++ b/target/arm/tcg/helper-sve.h
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_FLAGS_7(sve_fnmls_zpzzz_s, TCG_CALL_NO_RWG,
 DEF_HELPER_FLAGS_7(sve_fnmls_zpzzz_d, TCG_CALL_NO_RWG,
                    void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
 
+DEF_HELPER_FLAGS_7(sve_ah_fmls_zpzzz_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fmls_zpzzz_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fmls_zpzzz_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+
+DEF_HELPER_FLAGS_7(sve_ah_fnmla_zpzzz_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fnmla_zpzzz_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fnmla_zpzzz_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+
+DEF_HELPER_FLAGS_7(sve_ah_fnmls_zpzzz_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fnmls_zpzzz_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_7(sve_ah_fnmls_zpzzz_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
+
 DEF_HELPER_FLAGS_7(sve_fcmla_zpzzz_h, TCG_CALL_NO_RWG,
                    void, ptr, ptr, ptr, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_7(sve_fcmla_zpzzz_s, TCG_CALL_NO_RWG,
diff --git a/target/arm/tcg/sve_helper.c b/target/arm/tcg/sve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/sve_helper.c
+++ b/target/arm/tcg/sve_helper.c
@@ -XXX,XX +XXX,XX @@ DO_ZPZ_FP(flogb_d, float64, H1_8, do_float64_logb_as_int)
 
 static void do_fmla_zpzzz_h(void *vd, void *vn, void *vm, void *va, void *vg,
                             float_status *status, uint32_t desc,
-                            uint16_t neg1, uint16_t neg3)
+                            uint16_t neg1, uint16_t neg3, int flags)
 {
     intptr_t i = simd_oprsz(desc);
     uint64_t *g = vg;
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_h(void *vd, void *vn, void *vm, void *va, void *vg,
                 e1 = *(uint16_t *)(vn + H1_2(i)) ^ neg1;
                 e2 = *(uint16_t *)(vm + H1_2(i));
                 e3 = *(uint16_t *)(va + H1_2(i)) ^ neg3;
-                r = float16_muladd(e1, e2, e3, 0, status);
+                r = float16_muladd(e1, e2, e3, flags, status);
                 *(uint16_t *)(vd + H1_2(i)) = r;
             }
         } while (i & 63);
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_h(void *vd, void *vn, void *vm, void *va, void *vg,
 void HELPER(sve_fmla_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0);
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0, 0);
 }
 
 void HELPER(sve_fmls_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0x8000, 0);
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0x8000, 0, 0);
 }
 
 void HELPER(sve_fnmla_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0x8000, 0x8000);
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0x8000, 0x8000, 0);
 }
 
 void HELPER(sve_fnmls_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0x8000);
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0x8000, 0);
+}
+
+void HELPER(sve_ah_fmls_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
+                              void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product);
+}
+
+void HELPER(sve_ah_fnmla_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product | float_muladd_negate_c);
+}
+
+void HELPER(sve_ah_fnmls_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_h(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_c);
 }
 
 static void do_fmla_zpzzz_s(void *vd, void *vn, void *vm, void *va, void *vg,
                             float_status *status, uint32_t desc,
-                            uint32_t neg1, uint32_t neg3)
+                            uint32_t neg1, uint32_t neg3, int flags)
 {
     intptr_t i = simd_oprsz(desc);
     uint64_t *g = vg;
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_s(void *vd, void *vn, void *vm, void *va, void *vg,
                 e1 = *(uint32_t *)(vn + H1_4(i)) ^ neg1;
                 e2 = *(uint32_t *)(vm + H1_4(i));
                 e3 = *(uint32_t *)(va + H1_4(i)) ^ neg3;
-                r = float32_muladd(e1, e2, e3, 0, status);
+                r = float32_muladd(e1, e2, e3, flags, status);
                 *(uint32_t *)(vd + H1_4(i)) = r;
             }
         } while (i & 63);
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_s(void *vd, void *vn, void *vm, void *va, void *vg,
 void HELPER(sve_fmla_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0);
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0, 0);
 }
 
 void HELPER(sve_fmls_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0x80000000, 0);
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0x80000000, 0, 0);
 }
 
 void HELPER(sve_fnmla_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0x80000000, 0x80000000);
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0x80000000, 0x80000000, 0);
 }
 
 void HELPER(sve_fnmls_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0x80000000);
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0x80000000, 0);
+}
+
+void HELPER(sve_ah_fmls_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
+                              void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product);
+}
+
+void HELPER(sve_ah_fnmla_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product | float_muladd_negate_c);
+}
+
+void HELPER(sve_ah_fnmls_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_s(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_c);
 }
 
 static void do_fmla_zpzzz_d(void *vd, void *vn, void *vm, void *va, void *vg,
                             float_status *status, uint32_t desc,
-                            uint64_t neg1, uint64_t neg3)
+                            uint64_t neg1, uint64_t neg3, int flags)
 {
     intptr_t i = simd_oprsz(desc);
     uint64_t *g = vg;
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_d(void *vd, void *vn, void *vm, void *va, void *vg,
                 e1 = *(uint64_t *)(vn + i) ^ neg1;
                 e2 = *(uint64_t *)(vm + i);
                 e3 = *(uint64_t *)(va + i) ^ neg3;
-                r = float64_muladd(e1, e2, e3, 0, status);
+                r = float64_muladd(e1, e2, e3, flags, status);
                 *(uint64_t *)(vd + i) = r;
             }
         } while (i & 63);
@@ -XXX,XX +XXX,XX @@ static void do_fmla_zpzzz_d(void *vd, void *vn, void *vm, void *va, void *vg,
 void HELPER(sve_fmla_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, 0);
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, 0, 0);
 }
 
 void HELPER(sve_fmls_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
                               void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, INT64_MIN, 0);
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, INT64_MIN, 0, 0);
 }
 
 void HELPER(sve_fnmla_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, INT64_MIN, INT64_MIN);
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, INT64_MIN, INT64_MIN, 0);
 }
 
 void HELPER(sve_fnmls_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
-    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, INT64_MIN);
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, INT64_MIN, 0);
+}
+
+void HELPER(sve_ah_fmls_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
+                              void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product);
+}
+
+void HELPER(sve_ah_fnmla_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_product | float_muladd_negate_c);
+}
+
+void HELPER(sve_ah_fnmls_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
+                               void *vg, float_status *status, uint32_t desc)
+{
+    do_fmla_zpzzz_d(vd, vn, vm, va, vg, status, desc, 0, 0,
+                    float_muladd_negate_c);
 }
 
 /* Two operand floating-point comparison controlled by a predicate.
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ TRANS_FEAT(FCADD, aa64_sve, gen_gvec_fpst_zzzp, fcadd_fns[a->esz],
            a->rd, a->rn, a->rm, a->pg, a->rot | (s->fpcr_ah << 1),
            a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
-#define DO_FMLA(NAME, name) \
+#define DO_FMLA(NAME, name, ah_name)                                    \
     static gen_helper_gvec_5_ptr * const name##_fns[4] = {              \
         NULL, gen_helper_sve_##name##_h,                                \
         gen_helper_sve_##name##_s, gen_helper_sve_##name##_d            \
     };                                                                  \
-    TRANS_FEAT(NAME, aa64_sve, gen_gvec_fpst_zzzzp, name##_fns[a->esz], \
+    static gen_helper_gvec_5_ptr * const name##_ah_fns[4] = {           \
+        NULL, gen_helper_sve_##ah_name##_h,                             \
+        gen_helper_sve_##ah_name##_s, gen_helper_sve_##ah_name##_d      \
+    };                                                                  \
+    TRANS_FEAT(NAME, aa64_sve, gen_gvec_fpst_zzzzp,                     \
+               s->fpcr_ah ? name##_ah_fns[a->esz] : name##_fns[a->esz], \
                a->rd, a->rn, a->rm, a->ra, a->pg, 0,                    \
                a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
-DO_FMLA(FMLA_zpzzz, fmla_zpzzz)
-DO_FMLA(FMLS_zpzzz, fmls_zpzzz)
-DO_FMLA(FNMLA_zpzzz, fnmla_zpzzz)
-DO_FMLA(FNMLS_zpzzz, fnmls_zpzzz)
+/* We don't need an ah_fmla_zpzzz because fmla doesn't negate anything */
+DO_FMLA(FMLA_zpzzz, fmla_zpzzz, fmla_zpzzz)
+DO_FMLA(FMLS_zpzzz, fmls_zpzzz, ah_fmls_zpzzz)
+DO_FMLA(FNMLA_zpzzz, fnmla_zpzzz, ah_fnmla_zpzzz)
+DO_FMLA(FNMLS_zpzzz, fnmls_zpzzz, ah_fnmls_zpzzz)
 
 #undef DO_FMLA
 
-- 
2.34.1

The negation step in the SVE FTSSEL insn mustn't negate a NaN when
FPCR.AH is set.  Pass FPCR.AH to the helper via the SIMD data field
and use that to determine whether to do the negation.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/sve_helper.c    | 18 +++++++++++++++---
 target/arm/tcg/translate-sve.c |  4 ++--
 2 files changed, 17 insertions(+), 5 deletions(-)

The negation step in the SVE FTMAD insn mustn't negate a NaN when
FPCR.AH is set.  Pass FPCR.AH to the helper via the SIMD data field,
so we can select the correct behaviour.

Because the operand is known to be negative, negating the operand
is the same as taking the absolute value.  Defer this to the muladd
operation via flags, so that it happens after NaN detection, which
is correct for FPCR.AH.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/sve_helper.c    | 42 ++++++++++++++++++++++++++--------
 target/arm/tcg/translate-sve.c |  3 ++-
 2 files changed, 35 insertions(+), 10 deletions(-)

From: Richard Henderson <richard.henderson@linaro.org>

The negation step in FCMLA mustn't negate a NaN when FPCR.AH
is set. Handle this by passing FPCR.AH to the helper via the
SIMD data field, and use this to select whether to do the
negation via XOR or via the muladd negate_product flag.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-26-richard.henderson@linaro.org
[PMM: Expanded commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/translate-a64.c |  2 +-
 target/arm/tcg/vec_helper.c    | 66 ++++++++++++++++++++--------------
 2 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool trans_FCMLA_v(DisasContext *s, arg_FCMLA_v *a)
 
     gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
                       a->esz == MO_16 ? FPST_A64_F16 : FPST_A64,
-                      a->rot, fn[a->esz]);
+                      a->rot | (s->fpcr_ah << 2), fn[a->esz]);
     return true;
 }
 
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcmlah)(void *vd, void *vn, void *vm, void *va,
     uintptr_t opr_sz = simd_oprsz(desc);
     float16 *d = vd, *n = vn, *m = vm, *a = va;
     intptr_t flip = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
-    uint32_t neg_real = flip ^ neg_imag;
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float16 negx_imag, negx_real;
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 15;
-    neg_imag <<= 15;
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 15;
+    negx_imag = (negf_imag & ~fpcr_ah) << 15;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     for (i = 0; i < opr_sz / 2; i += 2) {
         float16 e2 = n[H2(i + flip)];
-        float16 e1 = m[H2(i + flip)] ^ neg_real;
+        float16 e1 = m[H2(i + flip)] ^ negx_real;
         float16 e4 = e2;
-        float16 e3 = m[H2(i + 1 - flip)] ^ neg_imag;
+        float16 e3 = m[H2(i + 1 - flip)] ^ negx_imag;
 
-        d[H2(i)] = float16_muladd(e2, e1, a[H2(i)], 0, fpst);
-        d[H2(i + 1)] = float16_muladd(e4, e3, a[H2(i + 1)], 0, fpst);
+        d[H2(i)] = float16_muladd(e2, e1, a[H2(i)], negf_real, fpst);
+        d[H2(i + 1)] = float16_muladd(e4, e3, a[H2(i + 1)], negf_imag, fpst);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcmlas)(void *vd, void *vn, void *vm, void *va,
     uintptr_t opr_sz = simd_oprsz(desc);
     float32 *d = vd, *n = vn, *m = vm, *a = va;
     intptr_t flip = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
-    uint32_t neg_real = flip ^ neg_imag;
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float32 negx_imag, negx_real;
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 31;
-    neg_imag <<= 31;
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 31;
+    negx_imag = (negf_imag & ~fpcr_ah) << 31;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     for (i = 0; i < opr_sz / 4; i += 2) {
         float32 e2 = n[H4(i + flip)];
-        float32 e1 = m[H4(i + flip)] ^ neg_real;
+        float32 e1 = m[H4(i + flip)] ^ negx_real;
         float32 e4 = e2;
-        float32 e3 = m[H4(i + 1 - flip)] ^ neg_imag;
+        float32 e3 = m[H4(i + 1 - flip)] ^ negx_imag;
 
-        d[H4(i)] = float32_muladd(e2, e1, a[H4(i)], 0, fpst);
-        d[H4(i + 1)] = float32_muladd(e4, e3, a[H4(i + 1)], 0, fpst);
+        d[H4(i)] = float32_muladd(e2, e1, a[H4(i)], negf_real, fpst);
+        d[H4(i + 1)] = float32_muladd(e4, e3, a[H4(i + 1)], negf_imag, fpst);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcmlad)(void *vd, void *vn, void *vm, void *va,
     uintptr_t opr_sz = simd_oprsz(desc);
     float64 *d = vd, *n = vn, *m = vm, *a = va;
     intptr_t flip = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint64_t neg_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
-    uint64_t neg_real = flip ^ neg_imag;
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float64 negx_real, negx_imag;
     uintptr_t i;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 63;
-    neg_imag <<= 63;
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (uint64_t)(negf_real & ~fpcr_ah) << 63;
+    negx_imag = (uint64_t)(negf_imag & ~fpcr_ah) << 63;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     for (i = 0; i < opr_sz / 8; i += 2) {
         float64 e2 = n[i + flip];
-        float64 e1 = m[i + flip] ^ neg_real;
+        float64 e1 = m[i + flip] ^ negx_real;
         float64 e4 = e2;
-        float64 e3 = m[i + 1 - flip] ^ neg_imag;
+        float64 e3 = m[i + 1 - flip] ^ negx_imag;
 
-        d[i] = float64_muladd(e2, e1, a[i], 0, fpst);
-        d[i + 1] = float64_muladd(e4, e3, a[i + 1], 0, fpst);
+        d[i] = float64_muladd(e2, e1, a[i], negf_real, fpst);
+        d[i + 1] = float64_muladd(e4, e3, a[i + 1], negf_imag, fpst);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

The negation step in FCMLA by index mustn't negate a NaN when
FPCR.AH is set. Use the same approach as vector FCMLA of
passing in FPCR.AH and using it to select whether to negate
by XOR or by the muladd negate_product flag.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-27-richard.henderson@linaro.org
[PMM: Expanded commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/translate-a64.c |  2 +-
 target/arm/tcg/vec_helper.c    | 44 ++++++++++++++++++++--------------
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static bool trans_FCMLA_vi(DisasContext *s, arg_FCMLA_vi *a)
     if (fp_access_check(s)) {
         gen_gvec_op4_fpst(s, a->q, a->rd, a->rn, a->rm, a->rd,
                           a->esz == MO_16 ? FPST_A64_F16 : FPST_A64,
-                          (a->idx << 2) | a->rot, fn);
+                          (s->fpcr_ah << 4) | (a->idx << 2) | a->rot, fn);
     }
     return true;
 }
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcmlah_idx)(void *vd, void *vn, void *vm, void *va,
     uintptr_t opr_sz = simd_oprsz(desc);
     float16 *d = vd, *n = vn, *m = vm, *a = va;
     intptr_t flip = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
     intptr_t index = extract32(desc, SIMD_DATA_SHIFT + 2, 2);
-    uint32_t neg_real = flip ^ neg_imag;
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 4, 1);
+    uint32_t negf_real = flip ^ negf_imag;
     intptr_t elements = opr_sz / sizeof(float16);
     intptr_t eltspersegment = MIN(16 / sizeof(float16), elements);
+    float16 negx_imag, negx_real;
     intptr_t i, j;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 15;
-    neg_imag <<= 15;
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 15;
+    negx_imag = (negf_imag & ~fpcr_ah) << 15;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     for (i = 0; i < elements; i += eltspersegment) {
         float16 mr = m[H2(i + 2 * index + 0)];
         float16 mi = m[H2(i + 2 * index + 1)];
-        float16 e1 = neg_real ^ (flip ? mi : mr);
-        float16 e3 = neg_imag ^ (flip ? mr : mi);
+        float16 e1 = negx_real ^ (flip ? mi : mr);
+        float16 e3 = negx_imag ^ (flip ? mr : mi);
 
         for (j = i; j < i + eltspersegment; j += 2) {
             float16 e2 = n[H2(j + flip)];
             float16 e4 = e2;
 
-            d[H2(j)] = float16_muladd(e2, e1, a[H2(j)], 0, fpst);
-            d[H2(j + 1)] = float16_muladd(e4, e3, a[H2(j + 1)], 0, fpst);
+            d[H2(j)] = float16_muladd(e2, e1, a[H2(j)], negf_real, fpst);
+            d[H2(j + 1)] = float16_muladd(e4, e3, a[H2(j + 1)], negf_imag, fpst);
         }
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fcmlas_idx)(void *vd, void *vn, void *vm, void *va,
     uintptr_t opr_sz = simd_oprsz(desc);
     float32 *d = vd, *n = vn, *m = vm, *a = va;
     intptr_t flip = extract32(desc, SIMD_DATA_SHIFT, 1);
-    uint32_t neg_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
     intptr_t index = extract32(desc, SIMD_DATA_SHIFT + 2, 2);
-    uint32_t neg_real = flip ^ neg_imag;
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 4, 1);
+    uint32_t negf_real = flip ^ negf_imag;
     intptr_t elements = opr_sz / sizeof(float32);
     intptr_t eltspersegment = MIN(16 / sizeof(float32), elements);
+    float32 negx_imag, negx_real;
     intptr_t i, j;
 
-    /* Shift boolean to the sign bit so we can xor to negate.  */
-    neg_real <<= 31;
-    neg_imag <<= 31;
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 31;
+    negx_imag = (negf_imag & ~fpcr_ah) << 31;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     for (i = 0; i < elements; i += eltspersegment) {
         float32 mr = m[H4(i + 2 * index + 0)];
         float32 mi = m[H4(i + 2 * index + 1)];
-        float32 e1 = neg_real ^ (flip ? mi : mr);
-        float32 e3 = neg_imag ^ (flip ? mr : mi);
+        float32 e1 = negx_real ^ (flip ? mi : mr);
+        float32 e3 = negx_imag ^ (flip ? mr : mi);
 
         for (j = i; j < i + eltspersegment; j += 2) {
             float32 e2 = n[H4(j + flip)];
             float32 e4 = e2;
 
-            d[H4(j)] = float32_muladd(e2, e1, a[H4(j)], 0, fpst);
-            d[H4(j + 1)] = float32_muladd(e4, e3, a[H4(j + 1)], 0, fpst);
+            d[H4(j)] = float32_muladd(e2, e1, a[H4(j)], negf_real, fpst);
+            d[H4(j + 1)] = float32_muladd(e4, e3, a[H4(j + 1)], negf_imag, fpst);
         }
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

The negation step in SVE FCMLA mustn't negate a NaN when FPCR.AH is
set.  Use the same approach as we did for A64 FCMLA of passing in
FPCR.AH and using it to select whether to negate by XOR or by the
muladd negate_product flag.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-28-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/sve_helper.c    | 69 +++++++++++++++++++++-------------
 target/arm/tcg/translate-sve.c |  2 +-
 2 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/target/arm/tcg/sve_helper.c b/target/arm/tcg/sve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/sve_helper.c
+++ b/target/arm/tcg/sve_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
     intptr_t j, i = simd_oprsz(desc);
-    unsigned rot = simd_data(desc);
-    bool flip = rot & 1;
-    float16 neg_imag, neg_real;
+    bool flip = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float16 negx_imag, negx_real;
     uint64_t *g = vg;
 
-    neg_imag = float16_set_sign(0, (rot & 2) != 0);
-    neg_real = float16_set_sign(0, rot == 1 || rot == 2);
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 15;
+    negx_imag = (negf_imag & ~fpcr_ah) << 15;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_h)(void *vd, void *vn, void *vm, void *va,
             mi = *(float16 *)(vm + H1_2(j));
 
             e2 = (flip ? ni : nr);
-            e1 = (flip ? mi : mr) ^ neg_real;
+            e1 = (flip ? mi : mr) ^ negx_real;
             e4 = e2;
-            e3 = (flip ? mr : mi) ^ neg_imag;
+            e3 = (flip ? mr : mi) ^ negx_imag;
 
             if (likely((pg >> (i & 63)) & 1)) {
                 d = *(float16 *)(va + H1_2(i));
-                d = float16_muladd(e2, e1, d, 0, status);
+                d = float16_muladd(e2, e1, d, negf_real, status);
                 *(float16 *)(vd + H1_2(i)) = d;
             }
             if (likely((pg >> (j & 63)) & 1)) {
                 d = *(float16 *)(va + H1_2(j));
-                d = float16_muladd(e4, e3, d, 0, status);
+                d = float16_muladd(e4, e3, d, negf_imag, status);
                 *(float16 *)(vd + H1_2(j)) = d;
             }
         } while (i & 63);
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
     intptr_t j, i = simd_oprsz(desc);
-    unsigned rot = simd_data(desc);
-    bool flip = rot & 1;
-    float32 neg_imag, neg_real;
+    bool flip = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float32 negx_imag, negx_real;
     uint64_t *g = vg;
 
-    neg_imag = float32_set_sign(0, (rot & 2) != 0);
-    neg_real = float32_set_sign(0, rot == 1 || rot == 2);
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (negf_real & ~fpcr_ah) << 31;
+    negx_imag = (negf_imag & ~fpcr_ah) << 31;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_s)(void *vd, void *vn, void *vm, void *va,
             mi = *(float32 *)(vm + H1_2(j));
 
             e2 = (flip ? ni : nr);
-            e1 = (flip ? mi : mr) ^ neg_real;
+            e1 = (flip ? mi : mr) ^ negx_real;
             e4 = e2;
-            e3 = (flip ? mr : mi) ^ neg_imag;
+            e3 = (flip ? mr : mi) ^ negx_imag;
 
             if (likely((pg >> (i & 63)) & 1)) {
                 d = *(float32 *)(va + H1_2(i));
-                d = float32_muladd(e2, e1, d, 0, status);
+                d = float32_muladd(e2, e1, d, negf_real, status);
                 *(float32 *)(vd + H1_2(i)) = d;
             }
             if (likely((pg >> (j & 63)) & 1)) {
                 d = *(float32 *)(va + H1_2(j));
-                d = float32_muladd(e4, e3, d, 0, status);
+                d = float32_muladd(e4, e3, d, negf_imag, status);
                 *(float32 *)(vd + H1_2(j)) = d;
             }
         } while (i & 63);
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
                                void *vg, float_status *status, uint32_t desc)
 {
     intptr_t j, i = simd_oprsz(desc);
-    unsigned rot = simd_data(desc);
-    bool flip = rot & 1;
-    float64 neg_imag, neg_real;
+    bool flip = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint32_t fpcr_ah = extract32(desc, SIMD_DATA_SHIFT + 2, 1);
+    uint32_t negf_imag = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
+    uint32_t negf_real = flip ^ negf_imag;
+    float64 negx_imag, negx_real;
     uint64_t *g = vg;
 
-    neg_imag = float64_set_sign(0, (rot & 2) != 0);
-    neg_real = float64_set_sign(0, rot == 1 || rot == 2);
+    /* With AH=0, use negx; with AH=1 use negf. */
+    negx_real = (uint64_t)(negf_real & ~fpcr_ah) << 63;
+    negx_imag = (uint64_t)(negf_imag & ~fpcr_ah) << 63;
+    negf_real = (negf_real & fpcr_ah ? float_muladd_negate_product : 0);
+    negf_imag = (negf_imag & fpcr_ah ? float_muladd_negate_product : 0);
 
     do {
         uint64_t pg = g[(i - 1) >> 6];
@@ -XXX,XX +XXX,XX @@ void HELPER(sve_fcmla_zpzzz_d)(void *vd, void *vn, void *vm, void *va,
             mi = *(float64 *)(vm + H1_2(j));
 
             e2 = (flip ? ni : nr);
-            e1 = (flip ? mi : mr) ^ neg_real;
+            e1 = (flip ? mi : mr) ^ negx_real;
             e4 = e2;
-            e3 = (flip ? mr : mi) ^ neg_imag;
+            e3 = (flip ? mr : mi) ^ negx_imag;
 
             if (likely((pg >> (i & 63)) & 1)) {
                 d = *(float64 *)(va + H1_2(i));
-                d = float64_muladd(e2, e1, d, 0, status);
+                d = float64_muladd(e2, e1, d, negf_real, status);
                 *(float64 *)(vd + H1_2(i)) = d;
             }
             if (likely((pg >> (j & 63)) & 1)) {
                 d = *(float64 *)(va + H1_2(j));
-                d = float64_muladd(e4, e3, d, 0, status);
+                d = float64_muladd(e4, e3, d, negf_imag, status);
                 *(float64 *)(vd + H1_2(j)) = d;
             }
         } while (i & 63);
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_5_ptr * const fcmla_fns[4] = {
     gen_helper_sve_fcmla_zpzzz_s, gen_helper_sve_fcmla_zpzzz_d,
 };
 TRANS_FEAT(FCMLA_zpzzz, aa64_sve, gen_gvec_fpst_zzzzp, fcmla_fns[a->esz],
-           a->rd, a->rn, a->rm, a->ra, a->pg, a->rot,
+           a->rd, a->rn, a->rm, a->ra, a->pg, a->rot | (s->fpcr_ah << 2),
            a->esz == MO_16 ? FPST_A64_F16 : FPST_A64)
 
 static gen_helper_gvec_4_ptr * const fcmla_idx_fns[4] = {
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Handle FPCR.AH's requirement to not negate the sign of a NaN
in FMLSL by element and vector, using the usual trick of
negating by XOR when AH=0 and by muladd flags when AH=1.

Since we have the CPUARMState* in the helper anyway, we can
look directly at env->vfp.fpcr and don't need toa pass in the
FPCR.AH value via the SIMD data word.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-31-richard.henderson@linaro.org
[PMM: commit message tweaked]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/vec_helper.c | 71 ++++++++++++++++++++++++-------------
 1 file changed, 46 insertions(+), 25 deletions(-)

diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ static uint64_t load4_f16(uint64_t *ptr, int is_q, int is_2)
  */
 
 static void do_fmlal(float32 *d, void *vn, void *vm, float_status *fpst,
-                     uint32_t desc, bool fz16)
+                     uint64_t negx, int negf, uint32_t desc, bool fz16)
 {
     intptr_t i, oprsz = simd_oprsz(desc);
-    int is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     int is_2 = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
     int is_q = oprsz == 16;
     uint64_t n_4, m_4;
 
-    /* Pre-load all of the f16 data, avoiding overlap issues.  */
-    n_4 = load4_f16(vn, is_q, is_2);
+    /*
+     * Pre-load all of the f16 data, avoiding overlap issues.
+     * Negate all inputs for AH=0 FMLSL at once.
+     */
+    n_4 = load4_f16(vn, is_q, is_2) ^ negx;
     m_4 = load4_f16(vm, is_q, is_2);
 
-    /* Negate all inputs for FMLSL at once.  */
-    if (is_s) {
-        n_4 ^= 0x8000800080008000ull;
-    }
-
     for (i = 0; i < oprsz / 4; i++) {
         float32 n_1 = float16_to_float32_by_bits(n_4 >> (i * 16), fz16);
         float32 m_1 = float16_to_float32_by_bits(m_4 >> (i * 16), fz16);
-        d[H4(i)] = float32_muladd(n_1, m_1, d[H4(i)], 0, fpst);
+        d[H4(i)] = float32_muladd(n_1, m_1, d[H4(i)], negf, fpst);
     }
     clear_tail(d, oprsz, simd_maxsz(desc));
 }
@@ -XXX,XX +XXX,XX @@ static void do_fmlal(float32 *d, void *vn, void *vm, float_status *fpst,
 void HELPER(gvec_fmlal_a32)(void *vd, void *vn, void *vm,
                             CPUARMState *env, uint32_t desc)
 {
-    do_fmlal(vd, vn, vm, &env->vfp.standard_fp_status, desc,
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint64_t negx = is_s ? 0x8000800080008000ull : 0;
+
+    do_fmlal(vd, vn, vm, &env->vfp.standard_fp_status, negx, 0, desc,
              get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a32));
 }
 
 void HELPER(gvec_fmlal_a64)(void *vd, void *vn, void *vm,
                             CPUARMState *env, uint32_t desc)
 {
-    do_fmlal(vd, vn, vm, &env->vfp.fp_status_a64, desc,
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint64_t negx = 0;
+    int negf = 0;
+
+    if (is_s) {
+        if (env->vfp.fpcr & FPCR_AH) {
+            negf = float_muladd_negate_product;
+        } else {
+            negx = 0x8000800080008000ull;
+        }
+    }
+    do_fmlal(vd, vn, vm, &env->vfp.fp_status_a64, negx, negf, desc,
              get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a64));
 }
 
@@ -XXX,XX +XXX,XX @@ void HELPER(sve2_fmlal_zzzw_s)(void *vd, void *vn, void *vm, void *va,
 }
 
 static void do_fmlal_idx(float32 *d, void *vn, void *vm, float_status *fpst,
-                         uint32_t desc, bool fz16)
+                         uint64_t negx, int negf, uint32_t desc, bool fz16)
 {
     intptr_t i, oprsz = simd_oprsz(desc);
-    int is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     int is_2 = extract32(desc, SIMD_DATA_SHIFT + 1, 1);
     int index = extract32(desc, SIMD_DATA_SHIFT + 2, 3);
     int is_q = oprsz == 16;
     uint64_t n_4;
     float32 m_1;
 
-    /* Pre-load all of the f16 data, avoiding overlap issues.  */
-    n_4 = load4_f16(vn, is_q, is_2);
-
-    /* Negate all inputs for FMLSL at once.  */
-    if (is_s) {
-        n_4 ^= 0x8000800080008000ull;
-    }
-
+    /*
+     * Pre-load all of the f16 data, avoiding overlap issues.
+     * Negate all inputs for AH=0 FMLSL at once.
+     */
+    n_4 = load4_f16(vn, is_q, is_2) ^ negx;
     m_1 = float16_to_float32_by_bits(((float16 *)vm)[H2(index)], fz16);
 
     for (i = 0; i < oprsz / 4; i++) {
         float32 n_1 = float16_to_float32_by_bits(n_4 >> (i * 16), fz16);
-        d[H4(i)] = float32_muladd(n_1, m_1, d[H4(i)], 0, fpst);
+        d[H4(i)] = float32_muladd(n_1, m_1, d[H4(i)], negf, fpst);
     }
     clear_tail(d, oprsz, simd_maxsz(desc));
 }
@@ -XXX,XX +XXX,XX @@ static void do_fmlal_idx(float32 *d, void *vn, void *vm, float_status *fpst,
 void HELPER(gvec_fmlal_idx_a32)(void *vd, void *vn, void *vm,
                                 CPUARMState *env, uint32_t desc)
 {
-    do_fmlal_idx(vd, vn, vm, &env->vfp.standard_fp_status, desc,
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint64_t negx = is_s ? 0x8000800080008000ull : 0;
+
+    do_fmlal_idx(vd, vn, vm, &env->vfp.standard_fp_status, negx, 0, desc,
                  get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a32));
 }
 
 void HELPER(gvec_fmlal_idx_a64)(void *vd, void *vn, void *vm,
                                 CPUARMState *env, uint32_t desc)
 {
-    do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status_a64, desc,
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
+    uint64_t negx = 0;
+    int negf = 0;
+
+    if (is_s) {
+        if (env->vfp.fpcr & FPCR_AH) {
+            negf = float_muladd_negate_product;
+        } else {
+            negx = 0x8000800080008000ull;
+        }
+    }
+    do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status_a64, negx, negf, desc,
                  get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a64));
 }
 
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Handle FPCR.AH's requirement to not negate the sign of a NaN in SVE
FMLSL (indexed), using the usual trick of negating by XOR when AH=0
and by muladd flags when AH=1.

Since we have the CPUARMState* in the helper anyway, we can
look directly at env->vfp.fpcr and don't need toa pass in the
FPCR.AH value via the SIMD data word.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-32-richard.henderson@linaro.org
[PMM: commit message tweaked]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/vec_helper.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(sve2_fmlal_zzxw_s)(void *vd, void *vn, void *vm, void *va,
                                CPUARMState *env, uint32_t desc)
 {
     intptr_t i, j, oprsz = simd_oprsz(desc);
-    uint16_t negn = extract32(desc, SIMD_DATA_SHIFT, 1) << 15;
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     intptr_t sel = extract32(desc, SIMD_DATA_SHIFT + 1, 1) * sizeof(float16);
     intptr_t idx = extract32(desc, SIMD_DATA_SHIFT + 2, 3) * sizeof(float16);
     float_status *status = &env->vfp.fp_status_a64;
     bool fz16 = get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a64);
+    int negx = 0, negf = 0;
+
+    if (is_s) {
+        if (env->vfp.fpcr & FPCR_AH) {
+            negf = float_muladd_negate_product;
+        } else {
+            negx = 0x8000;
+        }
+    }
 
     for (i = 0; i < oprsz; i += 16) {
         float16 mm_16 = *(float16 *)(vm + i + idx);
         float32 mm = float16_to_float32_by_bits(mm_16, fz16);
 
         for (j = 0; j < 16; j += sizeof(float32)) {
-            float16 nn_16 = *(float16 *)(vn + H1_2(i + j + sel)) ^ negn;
+            float16 nn_16 = *(float16 *)(vn + H1_2(i + j + sel)) ^ negx;
             float32 nn = float16_to_float32_by_bits(nn_16, fz16);
             float32 aa = *(float32 *)(va + H1_4(i + j));
 
             *(float32 *)(vd + H1_4(i + j)) =
-                float32_muladd(nn, mm, aa, 0, status);
+                float32_muladd(nn, mm, aa, negf, status);
         }
     }
 }
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Handle FPCR.AH's requirement to not negate the sign of a NaN in SVE
FMLSL (indexed), using the usual trick of negating by XOR when AH=0
and by muladd flags when AH=1.

Since we have the CPUARMState* in the helper anyway, we can
look directly at env->vfp.fpcr and don't need toa pass in the
FPCR.AH value via the SIMD data word.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-33-richard.henderson@linaro.org
[PMM: tweaked commit message]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/vec_helper.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(sve2_fmlal_zzzw_s)(void *vd, void *vn, void *vm, void *va,
                                CPUARMState *env, uint32_t desc)
 {
     intptr_t i, oprsz = simd_oprsz(desc);
-    uint16_t negn = extract32(desc, SIMD_DATA_SHIFT, 1) << 15;
+    bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     intptr_t sel = extract32(desc, SIMD_DATA_SHIFT + 1, 1) * sizeof(float16);
     float_status *status = &env->vfp.fp_status_a64;
     bool fz16 = get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a64);
+    int negx = 0, negf = 0;
+
+    if (is_s) {
+        if (env->vfp.fpcr & FPCR_AH) {
+            negf = float_muladd_negate_product;
+        } else {
+            negx = 0x8000;
+        }
+    }
 
     for (i = 0; i < oprsz; i += sizeof(float32)) {
-        float16 nn_16 = *(float16 *)(vn + H1_2(i + sel)) ^ negn;
+        float16 nn_16 = *(float16 *)(vn + H1_2(i + sel)) ^ negx;
         float16 mm_16 = *(float16 *)(vm + H1_2(i + sel));
         float32 nn = float16_to_float32_by_bits(nn_16, fz16);
         float32 mm = float16_to_float32_by_bits(mm_16, fz16);
         float32 aa = *(float32 *)(va + H1_4(i));
 
-        *(float32 *)(vd + H1_4(i)) = float32_muladd(nn, mm, aa, 0, status);
+        *(float32 *)(vd + H1_4(i)) = float32_muladd(nn, mm, aa, negf, status);
     }
 }
 
-- 
2.34.1

Now that we have completed the handling for FPCR.{AH,FIZ,NEP}, we
can enable FEAT_AFP for '-cpu max', and document that we support it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 docs/system/arm/emulation.rst | 1 +
 target/arm/tcg/cpu64.c        | 1 +
 2 files changed, 2 insertions(+)

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index XXXXXXX..XXXXXXX 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -XXX,XX +XXX,XX @@ the following architecture extensions:
 - FEAT_AA64EL3 (Support for AArch64 at EL3)
 - FEAT_AdvSIMD (Advanced SIMD Extension)
 - FEAT_AES (AESD and AESE instructions)
+- FEAT_AFP (Alternate floating-point behavior)
 - FEAT_Armv9_Crypto (Armv9 Cryptographic Extension)
 - FEAT_ASID16 (16 bit ASID)
 - FEAT_BBM at level 2 (Translation table break-before-make levels)
diff --git a/target/arm/tcg/cpu64.c b/target/arm/tcg/cpu64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/cpu64.c
+++ b/target/arm/tcg/cpu64.c
@@ -XXX,XX +XXX,XX @@ void aarch64_max_tcg_initfn(Object *obj)
     t = FIELD_DP64(t, ID_AA64MMFR1, XNX, 1);      /* FEAT_XNX */
     t = FIELD_DP64(t, ID_AA64MMFR1, ETS, 2);      /* FEAT_ETS2 */
     t = FIELD_DP64(t, ID_AA64MMFR1, HCX, 1);      /* FEAT_HCX */
+    t = FIELD_DP64(t, ID_AA64MMFR1, AFP, 1);      /* FEAT_AFP */
     t = FIELD_DP64(t, ID_AA64MMFR1, TIDCP1, 1);   /* FEAT_TIDCP1 */
     t = FIELD_DP64(t, ID_AA64MMFR1, CMOW, 1);     /* FEAT_CMOW */
     cpu->isar.id_aa64mmfr1 = t;
-- 
2.34.1

FEAT_RPRES implements an "increased precision" variant of the single
precision FRECPE and FRSQRTE instructions from an 8 bit to a 12
bit mantissa. This applies only when FPCR.AH == 1. Note that the
halfprec and double versions of these insns retain the 8 bit
precision regardless.

In this commit we add all the plumbing to make these instructions
call a new helper function when the increased-precision is in
effect. In the following commit we will provide the actual change
in behaviour in the helpers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu-features.h      |  5 +++++
 target/arm/helper.h            |  4 ++++
 target/arm/tcg/translate-a64.c | 34 ++++++++++++++++++++++++++++++----
 target/arm/tcg/translate-sve.c | 16 ++++++++++++++--
 target/arm/tcg/vec_helper.c    |  2 ++
 target/arm/vfp_helper.c        | 32 ++++++++++++++++++++++++++++++--
 6 files changed, 85 insertions(+), 8 deletions(-)

diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu-features.h
+++ b/target/arm/cpu-features.h
@@ -XXX,XX +XXX,XX @@ static inline bool isar_feature_aa64_mops(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, MOPS);
 }
 
+static inline bool isar_feature_aa64_rpres(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, RPRES);
+}
+
 static inline bool isar_feature_aa64_fp_simd(const ARMISARegisters *id)
 {
     /* We always set the AdvSIMD and FP fields identically.  */
diff --git a/target/arm/helper.h b/target/arm/helper.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_4(vfp_muladdh, f16, f16, f16, f16, fpst)
 
 DEF_HELPER_FLAGS_2(recpe_f16, TCG_CALL_NO_RWG, f16, f16, fpst)
 DEF_HELPER_FLAGS_2(recpe_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
+DEF_HELPER_FLAGS_2(recpe_rpres_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
 DEF_HELPER_FLAGS_2(recpe_f64, TCG_CALL_NO_RWG, f64, f64, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f16, TCG_CALL_NO_RWG, f16, f16, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
+DEF_HELPER_FLAGS_2(rsqrte_rpres_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f64, TCG_CALL_NO_RWG, f64, f64, fpst)
 DEF_HELPER_FLAGS_1(recpe_u32, TCG_CALL_NO_RWG, i32, i32)
 DEF_HELPER_FLAGS_1(rsqrte_u32, TCG_CALL_NO_RWG, i32, i32)
@@ -XXX,XX +XXX,XX @@ DEF_HELPER_FLAGS_4(gvec_vrintx_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_frecpe_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frecpe_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_4(gvec_frecpe_rpres_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frecpe_d, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_frsqrte_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frsqrte_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_4(gvec_frsqrte_rpres_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frsqrte_d, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_fcgt0_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -XXX,XX +XXX,XX @@ static const FPScalar1 f_scalar_frecpe = {
     gen_helper_recpe_f32,
     gen_helper_recpe_f64,
 };
-TRANS(FRECPE_s, do_fp1_scalar_ah, a, &f_scalar_frecpe, -1)
+static const FPScalar1 f_scalar_frecpe_rpres = {
+    gen_helper_recpe_f16,
+    gen_helper_recpe_rpres_f32,
+    gen_helper_recpe_f64,
+};
+TRANS(FRECPE_s, do_fp1_scalar_ah, a,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+      &f_scalar_frecpe_rpres : &f_scalar_frecpe, -1)
 
 static const FPScalar1 f_scalar_frecpx = {
     gen_helper_frecpx_f16,
@@ -XXX,XX +XXX,XX @@ static const FPScalar1 f_scalar_frsqrte = {
     gen_helper_rsqrte_f32,
     gen_helper_rsqrte_f64,
 };
-TRANS(FRSQRTE_s, do_fp1_scalar_ah, a, &f_scalar_frsqrte, -1)
+static const FPScalar1 f_scalar_frsqrte_rpres = {
+    gen_helper_rsqrte_f16,
+    gen_helper_rsqrte_rpres_f32,
+    gen_helper_rsqrte_f64,
+};
+TRANS(FRSQRTE_s, do_fp1_scalar_ah, a,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+      &f_scalar_frsqrte_rpres : &f_scalar_frsqrte, -1)
 
 static bool trans_FCVT_s_ds(DisasContext *s, arg_rr *a)
 {
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_2_ptr * const f_frecpe[] = {
     gen_helper_gvec_frecpe_s,
     gen_helper_gvec_frecpe_d,
 };
-TRANS(FRECPE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frecpe)
+static gen_helper_gvec_2_ptr * const f_frecpe_rpres[] = {
+    gen_helper_gvec_frecpe_h,
+    gen_helper_gvec_frecpe_rpres_s,
+    gen_helper_gvec_frecpe_d,
+};
+TRANS(FRECPE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ? f_frecpe_rpres : f_frecpe)
 
 static gen_helper_gvec_2_ptr * const f_frsqrte[] = {
     gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s,
     gen_helper_gvec_frsqrte_d,
 };
-TRANS(FRSQRTE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frsqrte)
+static gen_helper_gvec_2_ptr * const f_frsqrte_rpres[] = {
+    gen_helper_gvec_frsqrte_h,
+    gen_helper_gvec_frsqrte_rpres_s,
+    gen_helper_gvec_frsqrte_d,
+};
+TRANS(FRSQRTE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ? f_frsqrte_rpres : f_frsqrte)
 
 static bool trans_FCVTL_v(DisasContext *s, arg_qrr_e *a)
 {
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -XXX,XX +XXX,XX @@ static gen_helper_gvec_2_ptr * const frecpe_fns[] = {
     NULL,                     gen_helper_gvec_frecpe_h,
     gen_helper_gvec_frecpe_s, gen_helper_gvec_frecpe_d,
 };
-TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frecpe_fns[a->esz], a, 0)
+static gen_helper_gvec_2_ptr * const frecpe_rpres_fns[] = {
+    NULL,                           gen_helper_gvec_frecpe_h,
+    gen_helper_gvec_frecpe_rpres_s, gen_helper_gvec_frecpe_d,
+};
+TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_ah_arg_zz,
+           s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+           frecpe_rpres_fns[a->esz] : frecpe_fns[a->esz], a, 0)
 
 static gen_helper_gvec_2_ptr * const frsqrte_fns[] = {
     NULL,                      gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s, gen_helper_gvec_frsqrte_d,
 };
-TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frsqrte_fns[a->esz], a, 0)
+static gen_helper_gvec_2_ptr * const frsqrte_rpres_fns[] = {
+    NULL,                            gen_helper_gvec_frsqrte_h,
+    gen_helper_gvec_frsqrte_rpres_s, gen_helper_gvec_frsqrte_d,
+};
+TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_ah_arg_zz,
+           s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+           frsqrte_rpres_fns[a->esz] : frsqrte_fns[a->esz], a, 0)
 
 /*
  *** SVE Floating Point Compare with Zero Group
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(NAME)(void *vd, void *vn, float_status *stat, uint32_t desc)  \
 
 DO_2OP(gvec_frecpe_h, helper_recpe_f16, float16)
 DO_2OP(gvec_frecpe_s, helper_recpe_f32, float32)
+DO_2OP(gvec_frecpe_rpres_s, helper_recpe_rpres_f32, float32)
 DO_2OP(gvec_frecpe_d, helper_recpe_f64, float64)
 
 DO_2OP(gvec_frsqrte_h, helper_rsqrte_f16, float16)
 DO_2OP(gvec_frsqrte_s, helper_rsqrte_f32, float32)
+DO_2OP(gvec_frsqrte_rpres_s, helper_rsqrte_rpres_f32, float32)
 DO_2OP(gvec_frsqrte_d, helper_rsqrte_f64, float64)
 
 DO_2OP(gvec_vrintx_h, float16_round_to_int, float16)
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ uint32_t HELPER(recpe_f16)(uint32_t input, float_status *fpst)
     return make_float16(f16_val);
 }
 
-float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
+/*
+ * FEAT_RPRES means the f32 FRECPE has an "increased precision" variant
+ * which is used when FPCR.AH == 1.
+ */
+static float32 do_recpe_f32(float32 input, float_status *fpst, bool rpres)
 {
     float32 f32 = float32_squash_input_denormal(input, fpst);
     uint32_t f32_val = float32_val(f32);
@@ -XXX,XX +XXX,XX @@ float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
     return make_float32(f32_val);
 }
 
+float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
+{
+    return do_recpe_f32(input, fpst, false);
+}
+
+float32 HELPER(recpe_rpres_f32)(float32 input, float_status *fpst)
+{
+    return do_recpe_f32(input, fpst, true);
+}
+
 float64 HELPER(recpe_f64)(float64 input, float_status *fpst)
 {
     float64 f64 = float64_squash_input_denormal(input, fpst);
@@ -XXX,XX +XXX,XX @@ uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s)
     return make_float16(val);
 }
 
-float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
+/*
+ * FEAT_RPRES means the f32 FRSQRTE has an "increased precision" variant
+ * which is used when FPCR.AH == 1.
+ */
+static float32 do_rsqrte_f32(float32 input, float_status *s, bool rpres)
 {
     float32 f32 = float32_squash_input_denormal(input, s);
     uint32_t val = float32_val(f32);
@@ -XXX,XX +XXX,XX @@ float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
     return make_float32(val);
 }
 
+float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
+{
+    return do_rsqrte_f32(input, s, false);
+}
+
+float32 HELPER(rsqrte_rpres_f32)(float32 input, float_status *s)
+{
+    return do_rsqrte_f32(input, s, true);
+}
+
 float64 HELPER(rsqrte_f64)(float64 input, float_status *s)
 {
     float64 f64 = float64_squash_input_denormal(input, s);
-- 
2.34.1

Implement the increased precision variation of FRECPE.  In the
pseudocode this corresponds to the handling of the
"increasedprecision" boolean in the FPRecipEstimate() and
RecipEstimate() functions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/vfp_helper.c | 54 +++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static int recip_estimate(int input)
     return r;
 }
 
+/*
+ * Increased precision version:
+ * input is a 13 bit fixed point number
+ * input range 2048 .. 4095 for a number from 0.5 <= x < 1.0.
+ * result range 4096 .. 8191 for a number from 1.0 to 2.0
+ */
+static int recip_estimate_incprec(int input)
+{
+    int a, b, r;
+    assert(2048 <= input && input < 4096);
+    a = (input * 2) + 1;
+    /*
+     * The pseudocode expresses this as an operation on infinite
+     * precision reals where it calculates 2^25 / a and then looks
+     * at the error between that and the rounded-down-to-integer
+     * value to see if it should instead round up. We instead
+     * follow the same approach as the pseudocode for the 8-bit
+     * precision version, and calculate (2 * (2^25 / a)) as an
+     * integer so we can do the "add one and halve" to round it.
+     * So the 1 << 26 here is correct.
+     */
+    b = (1 << 26) / a;
+    r = (b + 1) >> 1;
+    assert(4096 <= r && r < 8192);
+    return r;
+}
+
 /*
  * Common wrapper to call recip_estimate
  *
@@ -XXX,XX +XXX,XX @@ static int recip_estimate(int input)
  * callee.
  */
 
-static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac)
+static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac,
+                                    bool increasedprecision)
 {
     uint32_t scaled, estimate;
     uint64_t result_frac;
@@ -XXX,XX +XXX,XX @@ static uint64_t call_recip_estimate(int *exp, int exp_off, uint64_t frac)
         }
     }
 
-    /* scaled = UInt('1':fraction<51:44>) */
-    scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8));
-    estimate = recip_estimate(scaled);
+    if (increasedprecision) {
+        /* scaled = UInt('1':fraction<51:41>) */
+        scaled = deposit32(1 << 11, 0, 11, extract64(frac, 41, 11));
+        estimate = recip_estimate_incprec(scaled);
+    } else {
+        /* scaled = UInt('1':fraction<51:44>) */
+        scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8));
+        estimate = recip_estimate(scaled);
+    }
 
     result_exp = exp_off - *exp;
-    result_frac = deposit64(0, 44, 8, estimate);
+    if (increasedprecision) {
+        result_frac = deposit64(0, 40, 12, estimate);
+    } else {
+        result_frac = deposit64(0, 44, 8, estimate);
+    }
     if (result_exp == 0) {
         result_frac = deposit64(result_frac >> 1, 51, 1, 1);
     } else if (result_exp == -1) {
@@ -XXX,XX +XXX,XX @@ uint32_t HELPER(recpe_f16)(uint32_t input, float_status *fpst)
     }
 
     f64_frac = call_recip_estimate(&f16_exp, 29,
-                                   ((uint64_t) f16_frac) << (52 - 10));
+                                   ((uint64_t) f16_frac) << (52 - 10), false);
 
     /* result = sign : result_exp<4:0> : fraction<51:42> */
     f16_val = deposit32(0, 15, 1, f16_sign);
@@ -XXX,XX +XXX,XX @@ static float32 do_recpe_f32(float32 input, float_status *fpst, bool rpres)
     }
 
     f64_frac = call_recip_estimate(&f32_exp, 253,
-                                   ((uint64_t) f32_frac) << (52 - 23));
+                                   ((uint64_t) f32_frac) << (52 - 23), rpres);
 
     /* result = sign : result_exp<7:0> : fraction<51:29> */
     f32_val = deposit32(0, 31, 1, f32_sign);
@@ -XXX,XX +XXX,XX @@ float64 HELPER(recpe_f64)(float64 input, float_status *fpst)
         return float64_set_sign(float64_zero, float64_is_neg(f64));
     }
 
-    f64_frac = call_recip_estimate(&f64_exp, 2045, f64_frac);
+    f64_frac = call_recip_estimate(&f64_exp, 2045, f64_frac, false);
 
     /* result = sign : result_exp<10:0> : fraction<51:0>; */
     f64_val = deposit64(0, 63, 1, f64_sign);
-- 
2.34.1

Implement the increased precision variation of FRSQRTE.  In the
pseudocode this corresponds to the handling of the
"increasedprecision" boolean in the FPRSqrtEstimate() and
RecipSqrtEstimate() functions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/vfp_helper.c | 77 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 64 insertions(+), 13 deletions(-)

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static int do_recip_sqrt_estimate(int a)
     return estimate;
 }
 
+static int do_recip_sqrt_estimate_incprec(int a)
+{
+    /*
+     * The Arm ARM describes the 12-bit precision version of RecipSqrtEstimate
+     * in terms of an infinite-precision floating point calculation of a
+     * square root. We implement this using the same kind of pure integer
+     * algorithm as the 8-bit mantissa, to get the same bit-for-bit result.
+     */
+    int64_t b, estimate;
 
-static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac)
+    assert(1024 <= a && a < 4096);
+    if (a < 2048) {
+        a = a * 2 + 1;
+    } else {
+        a = (a >> 1) << 1;
+        a = (a + 1) * 2;
+    }
+    b = 8192;
+    while (a * (b + 1) * (b + 1) < (1ULL << 39)) {
+        b += 1;
+    }
+    estimate = (b + 1) / 2;
+
+    assert(4096 <= estimate && estimate < 8192);
+
+    return estimate;
+}
+
+static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac,
+                                    bool increasedprecision)
 {
     int estimate;
     uint32_t scaled;
@@ -XXX,XX +XXX,XX @@ static uint64_t recip_sqrt_estimate(int *exp , int exp_off, uint64_t frac)
         frac = extract64(frac, 0, 51) << 1;
     }
 
-    if (*exp & 1) {
-        /* scaled = UInt('01':fraction<51:45>) */
-        scaled = deposit32(1 << 7, 0, 7, extract64(frac, 45, 7));
+    if (increasedprecision) {
+        if (*exp & 1) {
+            /* scaled = UInt('01':fraction<51:42>) */
+            scaled = deposit32(1 << 10, 0, 10, extract64(frac, 42, 10));
+        } else {
+            /* scaled = UInt('1':fraction<51:41>) */
+            scaled = deposit32(1 << 11, 0, 11, extract64(frac, 41, 11));
+        }
+        estimate = do_recip_sqrt_estimate_incprec(scaled);
     } else {
-        /* scaled = UInt('1':fraction<51:44>) */
-        scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8));
+        if (*exp & 1) {
+            /* scaled = UInt('01':fraction<51:45>) */
+            scaled = deposit32(1 << 7, 0, 7, extract64(frac, 45, 7));
+        } else {
+            /* scaled = UInt('1':fraction<51:44>) */
+            scaled = deposit32(1 << 8, 0, 8, extract64(frac, 44, 8));
+        }
+        estimate = do_recip_sqrt_estimate(scaled);
     }
-    estimate = do_recip_sqrt_estimate(scaled);
 
     *exp = (exp_off - *exp) / 2;
-    return extract64(estimate, 0, 8) << 44;
+    if (increasedprecision) {
+        return extract64(estimate, 0, 12) << 40;
+    } else {
+        return extract64(estimate, 0, 8) << 44;
+    }
 }
 
 uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s)
@@ -XXX,XX +XXX,XX @@ uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s)
 
     f64_frac = ((uint64_t) f16_frac) << (52 - 10);
 
-    f64_frac = recip_sqrt_estimate(&f16_exp, 44, f64_frac);
+    f64_frac = recip_sqrt_estimate(&f16_exp, 44, f64_frac, false);
 
     /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(2) */
     val = deposit32(0, 15, 1, f16_sign);
@@ -XXX,XX +XXX,XX @@ static float32 do_rsqrte_f32(float32 input, float_status *s, bool rpres)
 
     f64_frac = ((uint64_t) f32_frac) << 29;
 
-    f64_frac = recip_sqrt_estimate(&f32_exp, 380, f64_frac);
+    f64_frac = recip_sqrt_estimate(&f32_exp, 380, f64_frac, rpres);
 
-    /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(15) */
+    /*
+     * result = sign : result_exp<7:0> : estimate<7:0> : Zeros(15)
+     * or for increased precision
+     * result = sign : result_exp<7:0> : estimate<11:0> : Zeros(11)
+     */
     val = deposit32(0, 31, 1, f32_sign);
     val = deposit32(val, 23, 8, f32_exp);
-    val = deposit32(val, 15, 8, extract64(f64_frac, 52 - 8, 8));
+    if (rpres) {
+        val = deposit32(val, 11, 12, extract64(f64_frac, 52 - 12, 12));
+    } else {
+        val = deposit32(val, 15, 8, extract64(f64_frac, 52 - 8, 8));
+    }
     return make_float32(val);
 }
 
@@ -XXX,XX +XXX,XX @@ float64 HELPER(rsqrte_f64)(float64 input, float_status *s)
         return float64_zero;
     }
 
-    f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac);
+    f64_frac = recip_sqrt_estimate(&f64_exp, 3068, f64_frac, false);
 
     /* result = sign : result_exp<4:0> : estimate<7:0> : Zeros(44) */
     val = deposit64(0, 61, 1, f64_sign);
-- 
2.34.1

Now the emulation is complete, we can enable FEAT_RPRES for the 'max'
CPU type.

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index XXXXXXX..XXXXXXX 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -XXX,XX +XXX,XX @@ the following architecture extensions:
 - FEAT_RDM (Advanced SIMD rounding double multiply accumulate instructions)
 - FEAT_RME (Realm Management Extension) (NB: support status in QEMU is experimental)
 - FEAT_RNG (Random number generator)
+- FEAT_RPRES (Increased precision of FRECPE and FRSQRTE)
 - FEAT_S2FWB (Stage 2 forced Write-Back)
 - FEAT_SB (Speculation Barrier)
 - FEAT_SEL2 (Secure EL2)
diff --git a/target/arm/tcg/cpu64.c b/target/arm/tcg/cpu64.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/cpu64.c
+++ b/target/arm/tcg/cpu64.c
@@ -XXX,XX +XXX,XX @@ void aarch64_max_tcg_initfn(Object *obj)
     cpu->isar.id_aa64isar1 = t;
 
     t = cpu->isar.id_aa64isar2;
+    t = FIELD_DP64(t, ID_AA64ISAR2, RPRES, 1);    /* FEAT_RPRES */
     t = FIELD_DP64(t, ID_AA64ISAR2, MOPS, 1);     /* FEAT_MOPS */
     t = FIELD_DP64(t, ID_AA64ISAR2, BC, 1);       /* FEAT_HBC */
     t = FIELD_DP64(t, ID_AA64ISAR2, WFXT, 2);     /* FEAT_WFxT */
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Move ARMFPStatusFlavour to cpu.h with which to index
this array.  For now, place the array in an anonymous
union with the existing structures.  Adjust the order
of the existing structures to match the enum.

Simplify fpstatus_ptr() using the new array.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-7-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h           | 119 +++++++++++++++++++++----------------
 target/arm/tcg/translate.h |  64 +-------------------
 2 files changed, 70 insertions(+), 113 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct ARMMMUFaultInfo ARMMMUFaultInfo;
 
 typedef struct NVICState NVICState;
 
+/*
+ * Enum for indexing vfp.fp_status[].
+ *
+ * FPST_A32: is the "normal" fp status for AArch32 insns
+ * FPST_A64: is the "normal" fp status for AArch64 insns
+ * FPST_A32_F16: used for AArch32 half-precision calculations
+ * FPST_A64_F16: used for AArch64 half-precision calculations
+ * FPST_STD: the ARM "Standard FPSCR Value"
+ * FPST_STD_F16: used for half-precision
+ *       calculations with the ARM "Standard FPSCR Value"
+ * FPST_AH: used for the A64 insns which change behaviour
+ *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
+ *       and the reciprocal and square root estimate/step insns)
+ * FPST_AH_F16: used for the A64 insns which change behaviour
+ *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
+ *       and the reciprocal and square root estimate/step insns);
+ *       for half-precision
+ *
+ * Half-precision operations are governed by a separate
+ * flush-to-zero control bit in FPSCR:FZ16. We pass a separate
+ * status structure to control this.
+ *
+ * The "Standard FPSCR", ie default-NaN, flush-to-zero,
+ * round-to-nearest and is used by any operations (generally
+ * Neon) which the architecture defines as controlled by the
+ * standard FPSCR value rather than the FPSCR.
+ *
+ * The "standard FPSCR but for fp16 ops" is needed because
+ * the "standard FPSCR" tracks the FPSCR.FZ16 bit rather than
+ * using a fixed value for it.
+ *
+ * The ah_fp_status is needed because some insns have different
+ * behaviour when FPCR.AH == 1: they don't update cumulative
+ * exception flags, they act like FPCR.{FZ,FIZ} = {1,1} and
+ * they ignore FPCR.RMode. But they don't ignore FPCR.FZ16,
+ * which means we need an ah_fp_status_f16 as well.
+ *
+ * To avoid having to transfer exception bits around, we simply
+ * say that the FPSCR cumulative exception flags are the logical
+ * OR of the flags in the four fp statuses. This relies on the
+ * only thing which needs to read the exception flags being
+ * an explicit FPSCR read.
+ */
+typedef enum ARMFPStatusFlavour {
+    FPST_A32,
+    FPST_A64,
+    FPST_A32_F16,
+    FPST_A64_F16,
+    FPST_AH,
+    FPST_AH_F16,
+    FPST_STD,
+    FPST_STD_F16,
+} ARMFPStatusFlavour;
+#define FPST_COUNT  8
+
 typedef struct CPUArchState {
     /* Regs for current mode.  */
     uint32_t regs[16];
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
         /* Scratch space for aa32 neon expansion.  */
         uint32_t scratch[8];
 
-        /* There are a number of distinct float control structures:
-         *
-         *  fp_status_a32: is the "normal" fp status for AArch32 insns
-         *  fp_status_a64: is the "normal" fp status for AArch64 insns
-         *  fp_status_fp16_a32: used for AArch32 half-precision calculations
-         *  fp_status_fp16_a64: used for AArch64 half-precision calculations
-         *  standard_fp_status : the ARM "Standard FPSCR Value"
-         *  standard_fp_status_fp16 : used for half-precision
-         *       calculations with the ARM "Standard FPSCR Value"
-         *  ah_fp_status: used for the A64 insns which change behaviour
-         *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
-         *       and the reciprocal and square root estimate/step insns)
-         *  ah_fp_status_f16: used for the A64 insns which change behaviour
-         *       when FPCR.AH == 1 (bfloat16 conversions and multiplies,
-         *       and the reciprocal and square root estimate/step insns);
-         *       for half-precision
-         *
-         * Half-precision operations are governed by a separate
-         * flush-to-zero control bit in FPSCR:FZ16. We pass a separate
-         * status structure to control this.
-         *
-         * The "Standard FPSCR", ie default-NaN, flush-to-zero,
-         * round-to-nearest and is used by any operations (generally
-         * Neon) which the architecture defines as controlled by the
-         * standard FPSCR value rather than the FPSCR.
-         *
-         * The "standard FPSCR but for fp16 ops" is needed because
-         * the "standard FPSCR" tracks the FPSCR.FZ16 bit rather than
-         * using a fixed value for it.
-         *
-         * The ah_fp_status is needed because some insns have different
-         * behaviour when FPCR.AH == 1: they don't update cumulative
-         * exception flags, they act like FPCR.{FZ,FIZ} = {1,1} and
-         * they ignore FPCR.RMode. But they don't ignore FPCR.FZ16,
-         * which means we need an ah_fp_status_f16 as well.
-         *
-         * To avoid having to transfer exception bits around, we simply
-         * say that the FPSCR cumulative exception flags are the logical
-         * OR of the flags in the four fp statuses. This relies on the
-         * only thing which needs to read the exception flags being
-         * an explicit FPSCR read.
-         */
-        float_status fp_status_a32;
-        float_status fp_status_a64;
-        float_status fp_status_f16_a32;
-        float_status fp_status_f16_a64;
-        float_status standard_fp_status;
-        float_status standard_fp_status_f16;
-        float_status ah_fp_status;
-        float_status ah_fp_status_f16;
+        /* There are a number of distinct float control structures. */
+        union {
+            float_status fp_status[FPST_COUNT];
+            struct {
+                float_status fp_status_a32;
+                float_status fp_status_a64;
+                float_status fp_status_f16_a32;
+                float_status fp_status_f16_a64;
+                float_status ah_fp_status;
+                float_status ah_fp_status_f16;
+                float_status standard_fp_status;
+                float_status standard_fp_status_f16;
+            };
+        };
 
         uint64_t zcr_el[4];   /* ZCR_EL[1-3] */
         uint64_t smcr_el[4];  /* SMCR_EL[1-3] */
diff --git a/target/arm/tcg/translate.h b/target/arm/tcg/translate.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/translate.h
+++ b/target/arm/tcg/translate.h
@@ -XXX,XX +XXX,XX @@ static inline CPUARMTBFlags arm_tbflags_from_tb(const TranslationBlock *tb)
     return (CPUARMTBFlags){ tb->flags, tb->cs_base };
 }
 
-/*
- * Enum for argument to fpstatus_ptr().
- */
-typedef enum ARMFPStatusFlavour {
-    FPST_A32,
-    FPST_A64,
-    FPST_A32_F16,
-    FPST_A64_F16,
-    FPST_AH,
-    FPST_AH_F16,
-    FPST_STD,
-    FPST_STD_F16,
-} ARMFPStatusFlavour;
-
 /**
  * fpstatus_ptr: return TCGv_ptr to the specified fp_status field
  *
  * We have multiple softfloat float_status fields in the Arm CPU state struct
  * (see the comment in cpu.h for details). Return a TCGv_ptr which has
  * been set up to point to the requested field in the CPU state struct.
- * The options are:
- *
- * FPST_A32
- *   for AArch32 non-FP16 operations controlled by the FPCR
- * FPST_A64
- *   for AArch64 non-FP16 operations controlled by the FPCR
- * FPST_A32_F16
- *   for AArch32 operations controlled by the FPCR where FPCR.FZ16 is to be used
- * FPST_A64_F16
- *   for AArch64 operations controlled by the FPCR where FPCR.FZ16 is to be used
- * FPST_AH:
- *   for AArch64 operations which change behaviour when AH=1 (specifically,
- *   bfloat16 conversions and multiplies, and the reciprocal and square root
- *   estimate/step insns)
- * FPST_AH_F16:
- *   ditto, but for half-precision operations
- * FPST_STD
- *   for A32/T32 Neon operations using the "standard FPSCR value"
- * FPST_STD_F16
- *   as FPST_STD, but where FPCR.FZ16 is to be used
  */
 static inline TCGv_ptr fpstatus_ptr(ARMFPStatusFlavour flavour)
 {
     TCGv_ptr statusptr = tcg_temp_new_ptr();
-    int offset;
+    int offset = offsetof(CPUARMState, vfp.fp_status[flavour]);
 
-    switch (flavour) {
-    case FPST_A32:
-        offset = offsetof(CPUARMState, vfp.fp_status_a32);
-        break;
-    case FPST_A64:
-        offset = offsetof(CPUARMState, vfp.fp_status_a64);
-        break;
-    case FPST_A32_F16:
-        offset = offsetof(CPUARMState, vfp.fp_status_f16_a32);
-        break;
-    case FPST_A64_F16:
-        offset = offsetof(CPUARMState, vfp.fp_status_f16_a64);
-        break;
-    case FPST_AH:
-        offset = offsetof(CPUARMState, vfp.ah_fp_status);
-        break;
-    case FPST_AH_F16:
-        offset = offsetof(CPUARMState, vfp.ah_fp_status_f16);
-        break;
-    case FPST_STD:
-        offset = offsetof(CPUARMState, vfp.standard_fp_status);
-        break;
-    case FPST_STD_F16:
-        offset = offsetof(CPUARMState, vfp.standard_fp_status_f16);
-        break;
-    default:
-        g_assert_not_reached();
-    }
     tcg_gen_addi_ptr(statusptr, tcg_env, offset);
     return statusptr;
 }
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_STD_F16].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-8-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  1 -
 target/arm/cpu.c            |  4 ++--
 target/arm/tcg/mve_helper.c | 24 ++++++++++++------------
 target/arm/vfp_helper.c     |  8 ++++----
 4 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
                 float_status ah_fp_status;
                 float_status ah_fp_status_f16;
                 float_status standard_fp_status;
-                float_status standard_fp_status_f16;
             };
         };
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
     set_flush_to_zero(1, &env->vfp.standard_fp_status);
     set_flush_inputs_to_zero(1, &env->vfp.standard_fp_status);
     set_default_nan_mode(1, &env->vfp.standard_fp_status);
-    set_default_nan_mode(1, &env->vfp.standard_fp_status_f16);
+    set_default_nan_mode(1, &env->vfp.fp_status[FPST_STD_F16]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_a64);
     arm_set_default_fp_behaviours(&env->vfp.standard_fp_status);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a64);
-    arm_set_default_fp_behaviours(&env->vfp.standard_fp_status_f16);
+    arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_STD_F16]);
     arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status);
     set_flush_to_zero(1, &env->vfp.ah_fp_status);
     set_flush_inputs_to_zero(1, &env->vfp.ah_fp_status);
diff --git a/target/arm/tcg/mve_helper.c b/target/arm/tcg/mve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/mve_helper.c
+++ b/target/arm/tcg/mve_helper.c
@@ -XXX,XX +XXX,XX @@ DO_VMAXMINA(vminaw, 4, int32_t, uint32_t, DO_MIN)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ALL(vminnma, minnuma)
                 r[e] = 0;                                               \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(tm & 1)) {                                            \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_VCADD_FP(vfcadd270s, 4, float32, float32_add, float32_sub)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_VFMA(vfmss, 4, float32, true)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE * 2)) == 0) {          \
                 continue;                                               \
             }                                                           \
-            fpst0 = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :   \
+            fpst0 = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :  \
                 &env->vfp.standard_fp_status;                           \
             fpst1 = fpst0;                                              \
             if (!(mask & 1)) {                                          \
@@ -XXX,XX +XXX,XX @@ DO_VCMLA(vcmla270s, 4, float32, 3, DO_VCMLAS)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_SCALAR_ALL(vfmul_scalar, mul)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ACC_SCALAR(vfmas_scalars, 4, float32, DO_VFMAS_SCALARS)
         TYPE *m = vm;                                           \
         TYPE ra = (TYPE)ra_in;                                  \
         float_status *fpst = (ESIZE == 2) ?                     \
-            &env->vfp.standard_fp_status_f16 :                  \
+            &env->vfp.fp_status[FPST_STD_F16] :                 \
             &env->vfp.standard_fp_status;                       \
         for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {      \
             if (mask & 1) {                                     \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
             if ((mask & emask) == 0) {                                  \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
             if ((mask & emask) == 0) {                                  \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_VCMP_FP_BOTH(vfcmples, vfcmple_scalars, 4, float32, !DO_GT32)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
@@ -XXX,XX +XXX,XX @@ DO_VCVT_FIXED(vcvt_fu, 4, uint32_t, helper_vfp_touls_round_to_zero)
         float_status *fpst;                                             \
         float_status scratch_fpst;                                      \
         float_status *base_fpst = (ESIZE == 2) ?                        \
-            &env->vfp.standard_fp_status_f16 :                          \
+            &env->vfp.fp_status[FPST_STD_F16] :                         \
             &env->vfp.standard_fp_status;                               \
         uint32_t prev_rmode = get_float_rounding_mode(base_fpst);       \
         set_float_rounding_mode(rmode, base_fpst);                      \
@@ -XXX,XX +XXX,XX @@ void HELPER(mve_vcvtt_hs)(CPUARMState *env, void *vd, void *vm)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.standard_fp_status_f16 :    \
+            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
                 &env->vfp.standard_fp_status;                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     /* FZ16 does not generate an input denormal exception.  */
     a32_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32)
           & ~float_flag_input_denormal_flushed);
-    a32_flags |= (get_float_exception_flags(&env->vfp.standard_fp_status_f16)
+    a32_flags |= (get_float_exception_flags(&env->vfp.fp_status[FPST_STD_F16])
           & ~float_flag_input_denormal_flushed);
 
     a64_flags |= get_float_exception_flags(&env->vfp.fp_status_a64);
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a32);
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a64);
     set_float_exception_flags(0, &env->vfp.standard_fp_status);
-    set_float_exception_flags(0, &env->vfp.standard_fp_status_f16);
+    set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD_F16]);
     set_float_exception_flags(0, &env->vfp.ah_fp_status);
     set_float_exception_flags(0, &env->vfp.ah_fp_status_f16);
 }
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         bool ftz_enabled = val & FPCR_FZ16;
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
-        set_flush_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16);
+        set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]);
         set_flush_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
-        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.standard_fp_status_f16);
+        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
     }
     if (changed & FPCR_FZ) {
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_STD].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-9-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  1 -
 target/arm/cpu.c            |  8 ++++----
 target/arm/tcg/mve_helper.c | 28 ++++++++++++++--------------
 target/arm/tcg/vec_helper.c |  4 ++--
 target/arm/vfp_helper.c     |  4 ++--
 5 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
                 float_status fp_status_f16_a64;
                 float_status ah_fp_status;
                 float_status ah_fp_status_f16;
-                float_status standard_fp_status;
             };
         };
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
         env->sau.ctrl = 0;
     }
 
-    set_flush_to_zero(1, &env->vfp.standard_fp_status);
-    set_flush_inputs_to_zero(1, &env->vfp.standard_fp_status);
-    set_default_nan_mode(1, &env->vfp.standard_fp_status);
+    set_flush_to_zero(1, &env->vfp.fp_status[FPST_STD]);
+    set_flush_inputs_to_zero(1, &env->vfp.fp_status[FPST_STD]);
+    set_default_nan_mode(1, &env->vfp.fp_status[FPST_STD]);
     set_default_nan_mode(1, &env->vfp.fp_status[FPST_STD_F16]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_a64);
-    arm_set_default_fp_behaviours(&env->vfp.standard_fp_status);
+    arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_STD]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a64);
     arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_STD_F16]);
diff --git a/target/arm/tcg/mve_helper.c b/target/arm/tcg/mve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/mve_helper.c
+++ b/target/arm/tcg/mve_helper.c
@@ -XXX,XX +XXX,XX @@ DO_VMAXMINA(vminaw, 4, int32_t, uint32_t, DO_MIN)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ALL(vminnma, minnuma)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(tm & 1)) {                                            \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCADD_FP(vfcadd270s, 4, float32, float32_add, float32_sub)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VFMA(vfmss, 4, float32, true)
                 continue;                                               \
             }                                                           \
             fpst0 = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :  \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             fpst1 = fpst0;                                              \
             if (!(mask & 1)) {                                          \
                 scratch_fpst = *fpst0;                                  \
@@ -XXX,XX +XXX,XX @@ DO_VCMLA(vcmla270s, 4, float32, 3, DO_VCMLAS)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_SCALAR_ALL(vfmul_scalar, mul)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ACC_SCALAR(vfmas_scalars, 4, float32, DO_VFMAS_SCALARS)
         TYPE ra = (TYPE)ra_in;                                  \
         float_status *fpst = (ESIZE == 2) ?                     \
             &env->vfp.fp_status[FPST_STD_F16] :                 \
-            &env->vfp.standard_fp_status;                       \
+            &env->vfp.fp_status[FPST_STD];                       \
         for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {      \
             if (mask & 1) {                                     \
                 TYPE v = m[H##ESIZE(e)];                        \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCMP_FP_BOTH(vfcmples, vfcmple_scalars, 4, float32, !DO_GT32)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCVT_FIXED(vcvt_fu, 4, uint32_t, helper_vfp_touls_round_to_zero)
         float_status scratch_fpst;                                      \
         float_status *base_fpst = (ESIZE == 2) ?                        \
             &env->vfp.fp_status[FPST_STD_F16] :                         \
-            &env->vfp.standard_fp_status;                               \
+            &env->vfp.fp_status[FPST_STD];                               \
         uint32_t prev_rmode = get_float_rounding_mode(base_fpst);       \
         set_float_rounding_mode(rmode, base_fpst);                      \
         for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {              \
@@ -XXX,XX +XXX,XX @@ static void do_vcvt_sh(CPUARMState *env, void *vd, void *vm, int top)
     unsigned e;
     float_status *fpst;
     float_status scratch_fpst;
-    float_status *base_fpst = &env->vfp.standard_fp_status;
+    float_status *base_fpst = &env->vfp.fp_status[FPST_STD];
     bool old_fz = get_flush_to_zero(base_fpst);
     set_flush_to_zero(false, base_fpst);
     for (e = 0; e < 16 / 4; e++, mask >>= 4) {
@@ -XXX,XX +XXX,XX @@ static void do_vcvt_hs(CPUARMState *env, void *vd, void *vm, int top)
     unsigned e;
     float_status *fpst;
     float_status scratch_fpst;
-    float_status *base_fpst = &env->vfp.standard_fp_status;
+    float_status *base_fpst = &env->vfp.fp_status[FPST_STD];
     bool old_fiz = get_flush_inputs_to_zero(base_fpst);
     set_flush_inputs_to_zero(false, base_fpst);
     for (e = 0; e < 16 / 4; e++, mask >>= 4) {
@@ -XXX,XX +XXX,XX @@ void HELPER(mve_vcvtt_hs)(CPUARMState *env, void *vd, void *vm)
                 continue;                                               \
             }                                                           \
             fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.standard_fp_status;                           \
+                &env->vfp.fp_status[FPST_STD];                           \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_a32)(void *vd, void *vn, void *vm,
     bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     uint64_t negx = is_s ? 0x8000800080008000ull : 0;
 
-    do_fmlal(vd, vn, vm, &env->vfp.standard_fp_status, negx, 0, desc,
+    do_fmlal(vd, vn, vm, &env->vfp.fp_status[FPST_STD], negx, 0, desc,
              get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a32));
 }
 
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_idx_a32)(void *vd, void *vn, void *vm,
     bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     uint64_t negx = is_s ? 0x8000800080008000ull : 0;
 
-    do_fmlal_idx(vd, vn, vm, &env->vfp.standard_fp_status, negx, 0, desc,
+    do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status[FPST_STD], negx, 0, desc,
                  get_flush_inputs_to_zero(&env->vfp.fp_status_f16_a32));
 }
 
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     uint32_t a32_flags = 0, a64_flags = 0;
 
     a32_flags |= get_float_exception_flags(&env->vfp.fp_status_a32);
-    a32_flags |= get_float_exception_flags(&env->vfp.standard_fp_status);
+    a32_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_STD]);
     /* FZ16 does not generate an input denormal exception.  */
     a32_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a32)
           & ~float_flag_input_denormal_flushed);
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.fp_status_a64);
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a32);
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a64);
-    set_float_exception_flags(0, &env->vfp.standard_fp_status);
+    set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD_F16]);
     set_float_exception_flags(0, &env->vfp.ah_fp_status);
     set_float_exception_flags(0, &env->vfp.ah_fp_status_f16);
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_AH_F16].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-10-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h        |  3 +--
 target/arm/cpu.c        |  2 +-
 target/arm/vfp_helper.c | 10 +++++-----
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct NVICState NVICState;
  * behaviour when FPCR.AH == 1: they don't update cumulative
  * exception flags, they act like FPCR.{FZ,FIZ} = {1,1} and
  * they ignore FPCR.RMode. But they don't ignore FPCR.FZ16,
- * which means we need an ah_fp_status_f16 as well.
+ * which means we need an FPST_AH_F16 as well.
  *
  * To avoid having to transfer exception bits around, we simply
  * say that the FPSCR cumulative exception flags are the logical
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
                 float_status fp_status_f16_a32;
                 float_status fp_status_f16_a64;
                 float_status ah_fp_status;
-                float_status ah_fp_status_f16;
             };
         };
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
     arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status);
     set_flush_to_zero(1, &env->vfp.ah_fp_status);
     set_flush_inputs_to_zero(1, &env->vfp.ah_fp_status);
-    arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status_f16);
+    arm_set_ah_fp_behaviours(&env->vfp.fp_status[FPST_AH_F16]);
 
 #ifndef CONFIG_USER_ONLY
     if (kvm_enabled()) {
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     a64_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
           & ~(float_flag_input_denormal_flushed | float_flag_input_denormal_used));
     /*
-     * We do not merge in flags from ah_fp_status or ah_fp_status_f16, because
+     * We do not merge in flags from ah_fp_status or FPST_AH_F16, because
      * they are used for insns that must not set the cumulative exception bits.
      */
 
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD_F16]);
     set_float_exception_flags(0, &env->vfp.ah_fp_status);
-    set_float_exception_flags(0, &env->vfp.ah_fp_status_f16);
+    set_float_exception_flags(0, &env->vfp.fp_status[FPST_AH_F16]);
 }
 
 static void vfp_sync_and_clear_float_status_exc_flags(CPUARMState *env)
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]);
-        set_flush_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
+        set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_AH_F16]);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a32);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_f16_a64);
         set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_STD_F16]);
-        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.ah_fp_status_f16);
+        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_AH_F16]);
     }
     if (changed & FPCR_FZ) {
         bool ftz_enabled = val & FPCR_FZ;
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64);
         set_default_nan_mode(dnan_enabled, &env->vfp.ah_fp_status);
-        set_default_nan_mode(dnan_enabled, &env->vfp.ah_fp_status_f16);
+        set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_AH_F16]);
     }
     if (changed & FPCR_AH) {
         bool ah_enabled = val & FPCR_AH;
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_AH].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-11-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h        | 3 +--
 target/arm/cpu.c        | 6 +++---
 target/arm/vfp_helper.c | 6 +++---
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct NVICState NVICState;
  * the "standard FPSCR" tracks the FPSCR.FZ16 bit rather than
  * using a fixed value for it.
  *
- * The ah_fp_status is needed because some insns have different
+ * FPST_AH is needed because some insns have different
  * behaviour when FPCR.AH == 1: they don't update cumulative
  * exception flags, they act like FPCR.{FZ,FIZ} = {1,1} and
  * they ignore FPCR.RMode. But they don't ignore FPCR.FZ16,
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
                 float_status fp_status_a64;
                 float_status fp_status_f16_a32;
                 float_status fp_status_f16_a64;
-                float_status ah_fp_status;
             };
         };
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a32);
     arm_set_default_fp_behaviours(&env->vfp.fp_status_f16_a64);
     arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_STD_F16]);
-    arm_set_ah_fp_behaviours(&env->vfp.ah_fp_status);
-    set_flush_to_zero(1, &env->vfp.ah_fp_status);
-    set_flush_inputs_to_zero(1, &env->vfp.ah_fp_status);
+    arm_set_ah_fp_behaviours(&env->vfp.fp_status[FPST_AH]);
+    set_flush_to_zero(1, &env->vfp.fp_status[FPST_AH]);
+    set_flush_inputs_to_zero(1, &env->vfp.fp_status[FPST_AH]);
     arm_set_ah_fp_behaviours(&env->vfp.fp_status[FPST_AH_F16]);
 
 #ifndef CONFIG_USER_ONLY
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
     a64_flags |= (get_float_exception_flags(&env->vfp.fp_status_f16_a64)
           & ~(float_flag_input_denormal_flushed | float_flag_input_denormal_used));
     /*
-     * We do not merge in flags from ah_fp_status or FPST_AH_F16, because
+     * We do not merge in flags from FPST_AH or FPST_AH_F16, because
      * they are used for insns that must not set the cumulative exception bits.
      */
 
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
     set_float_exception_flags(0, &env->vfp.fp_status_f16_a64);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_STD_F16]);
-    set_float_exception_flags(0, &env->vfp.ah_fp_status);
+    set_float_exception_flags(0, &env->vfp.fp_status[FPST_AH]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_AH_F16]);
 }
 
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_a64);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a32);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_f16_a64);
-        set_default_nan_mode(dnan_enabled, &env->vfp.ah_fp_status);
+        set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_AH]);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_AH_F16]);
     }
     if (changed & FPCR_AH) {
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_A64_F16].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  1 -
 target/arm/cpu.c            |  2 +-
 target/arm/tcg/sme_helper.c |  2 +-
 target/arm/tcg/vec_helper.c |  9 ++++-----
 target/arm/vfp_helper.c     | 16 ++++++++--------
 5 files changed, 14 insertions(+), 16 deletions(-)

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_A32_F16].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-13-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  1 -
 target/arm/cpu.c            |  2 +-
 target/arm/tcg/vec_helper.c |  4 ++--
 target/arm/vfp_helper.c     | 14 +++++++-------
 4 files changed, 10 insertions(+), 11 deletions(-)

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_A64].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-14-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  1 -
 target/arm/cpu.c            |  2 +-
 target/arm/tcg/sme_helper.c |  2 +-
 target/arm/tcg/vec_helper.c | 10 +++++-----
 target/arm/vfp_helper.c     | 16 ++++++++--------
 5 files changed, 15 insertions(+), 16 deletions(-)

From: Richard Henderson <richard.henderson@linaro.org>

Replace with fp_status[FPST_A32].  As this was the last of the
old structures, we can remove the anonymous union and struct.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-15-richard.henderson@linaro.org
[PMM: tweak to account for change to is_ebf()]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu.h            |  7 +------
 target/arm/cpu.c            |  2 +-
 target/arm/tcg/vec_helper.c |  2 +-
 target/arm/vfp_helper.c     | 18 +++++++++---------
 4 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -XXX,XX +XXX,XX @@ typedef struct CPUArchState {
         uint32_t scratch[8];
 
         /* There are a number of distinct float control structures. */
-        union {
-            float_status fp_status[FPST_COUNT];
-            struct {
-                float_status fp_status_a32;
-            };
-        };
+        float_status fp_status[FPST_COUNT];
 
         uint64_t zcr_el[4];   /* ZCR_EL[1-3] */
         uint64_t smcr_el[4];  /* SMCR_EL[1-3] */
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -XXX,XX +XXX,XX @@ static void arm_cpu_reset_hold(Object *obj, ResetType type)
     set_flush_inputs_to_zero(1, &env->vfp.fp_status[FPST_STD]);
     set_default_nan_mode(1, &env->vfp.fp_status[FPST_STD]);
     set_default_nan_mode(1, &env->vfp.fp_status[FPST_STD_F16]);
-    arm_set_default_fp_behaviours(&env->vfp.fp_status_a32);
+    arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_A32]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_A64]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_STD]);
     arm_set_default_fp_behaviours(&env->vfp.fp_status[FPST_A32_F16]);
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ bool is_ebf(CPUARMState *env, float_status *statusp, float_status *oddstatusp)
      */
     bool ebf = is_a64(env) && env->vfp.fpcr & FPCR_EBF;
 
-    *statusp = is_a64(env) ? env->vfp.fp_status[FPST_A64] : env->vfp.fp_status_a32;
+    *statusp = env->vfp.fp_status[is_a64(env) ? FPST_A64 : FPST_A32];
     set_default_nan_mode(true, statusp);
 
     if (ebf) {
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static uint32_t vfp_get_fpsr_from_host(CPUARMState *env)
 {
     uint32_t a32_flags = 0, a64_flags = 0;
 
-    a32_flags |= get_float_exception_flags(&env->vfp.fp_status_a32);
+    a32_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_A32]);
     a32_flags |= get_float_exception_flags(&env->vfp.fp_status[FPST_STD]);
     /* FZ16 does not generate an input denormal exception.  */
     a32_flags |= (get_float_exception_flags(&env->vfp.fp_status[FPST_A32_F16])
@@ -XXX,XX +XXX,XX @@ static void vfp_clear_float_status_exc_flags(CPUARMState *env)
      * values. The caller should have arranged for env->vfp.fpsr to
      * be the architecturally up-to-date exception flag information first.
      */
-    set_float_exception_flags(0, &env->vfp.fp_status_a32);
+    set_float_exception_flags(0, &env->vfp.fp_status[FPST_A32]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_A64]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_A32_F16]);
     set_float_exception_flags(0, &env->vfp.fp_status[FPST_A64_F16]);
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
             i = float_round_to_zero;
             break;
         }
-        set_float_rounding_mode(i, &env->vfp.fp_status_a32);
+        set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A32]);
         set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A64]);
         set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A32_F16]);
         set_float_rounding_mode(i, &env->vfp.fp_status[FPST_A64_F16]);
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
     }
     if (changed & FPCR_FZ) {
         bool ftz_enabled = val & FPCR_FZ;
-        set_flush_to_zero(ftz_enabled, &env->vfp.fp_status_a32);
+        set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32]);
         set_flush_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A64]);
         /* FIZ is A64 only so FZ always makes A32 code flush inputs to zero */
-        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status_a32);
+        set_flush_inputs_to_zero(ftz_enabled, &env->vfp.fp_status[FPST_A32]);
     }
     if (changed & (FPCR_FZ | FPCR_AH | FPCR_FIZ)) {
         /*
@@ -XXX,XX +XXX,XX @@ static void vfp_set_fpcr_to_host(CPUARMState *env, uint32_t val, uint32_t mask)
     }
     if (changed & FPCR_DN) {
         bool dnan_enabled = val & FPCR_DN;
-        set_default_nan_mode(dnan_enabled, &env->vfp.fp_status_a32);
+        set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A32]);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A64]);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A32_F16]);
         set_default_nan_mode(dnan_enabled, &env->vfp.fp_status[FPST_A64_F16]);
@@ -XXX,XX +XXX,XX @@ void VFP_HELPER(cmpe, P)(ARGTYPE a, ARGTYPE b, CPUARMState *env) \
         FLOATTYPE ## _compare(a, b, &env->vfp.FPST)); \
 }
 DO_VFP_cmp(h, float16, dh_ctype_f16, fp_status[FPST_A32_F16])
-DO_VFP_cmp(s, float32, float32, fp_status_a32)
-DO_VFP_cmp(d, float64, float64, fp_status_a32)
+DO_VFP_cmp(s, float32, float32, fp_status[FPST_A32])
+DO_VFP_cmp(d, float64, float64, fp_status[FPST_A32])
 #undef DO_VFP_cmp
 
 /* Integer to float and float to integer conversions */
@@ -XXX,XX +XXX,XX @@ uint64_t HELPER(fjcvtzs)(float64 value, float_status *status)
 
 uint32_t HELPER(vjcvt)(float64 value, CPUARMState *env)
 {
-    uint64_t pair = HELPER(fjcvtzs)(value, &env->vfp.fp_status_a32);
+    uint64_t pair = HELPER(fjcvtzs)(value, &env->vfp.fp_status[FPST_A32]);
     uint32_t result = pair;
     uint32_t z = (pair >> 32) == 0;
 
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Select on index instead of pointer.
No functional change.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-16-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/mve_helper.c | 40 +++++++++++++------------------------
 1 file changed, 14 insertions(+), 26 deletions(-)

diff --git a/target/arm/tcg/mve_helper.c b/target/arm/tcg/mve_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/mve_helper.c
+++ b/target/arm/tcg/mve_helper.c
@@ -XXX,XX +XXX,XX @@ DO_VMAXMINA(vminaw, 4, int32_t, uint32_t, DO_MIN)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ALL(vminnma, minnuma)
                 r[e] = 0;                                               \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(tm & 1)) {                                            \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCADD_FP(vfcadd270s, 4, float32, float32_add, float32_sub)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VFMA(vfmss, 4, float32, true)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE * 2)) == 0) {          \
                 continue;                                               \
             }                                                           \
-            fpst0 = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :  \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst0 = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             fpst1 = fpst0;                                              \
             if (!(mask & 1)) {                                          \
                 scratch_fpst = *fpst0;                                  \
@@ -XXX,XX +XXX,XX @@ DO_VCMLA(vcmla270s, 4, float32, 3, DO_VCMLAS)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_SCALAR_ALL(vfmul_scalar, mul)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_2OP_FP_ACC_SCALAR(vfmas_scalars, 4, float32, DO_VFMAS_SCALARS)
         unsigned e;                                             \
         TYPE *m = vm;                                           \
         TYPE ra = (TYPE)ra_in;                                  \
-        float_status *fpst = (ESIZE == 2) ?                     \
-            &env->vfp.fp_status[FPST_STD_F16] :                 \
-            &env->vfp.fp_status[FPST_STD];                       \
+        float_status *fpst =                                    \
+            &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
         for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {      \
             if (mask & 1) {                                     \
                 TYPE v = m[H##ESIZE(e)];                        \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
             if ((mask & emask) == 0) {                                  \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_FP_VMAXMINV(vminnmavs, 4, float32, true, float32_minnum)
             if ((mask & emask) == 0) {                                  \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & (1 << (e * ESIZE)))) {                         \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCMP_FP_BOTH(vfcmples, vfcmple_scalars, 4, float32, !DO_GT32)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
@@ -XXX,XX +XXX,XX @@ DO_VCVT_FIXED(vcvt_fu, 4, uint32_t, helper_vfp_touls_round_to_zero)
         unsigned e;                                                     \
         float_status *fpst;                                             \
         float_status scratch_fpst;                                      \
-        float_status *base_fpst = (ESIZE == 2) ?                        \
-            &env->vfp.fp_status[FPST_STD_F16] :                         \
-            &env->vfp.fp_status[FPST_STD];                               \
+        float_status *base_fpst =                                       \
+            &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD];  \
         uint32_t prev_rmode = get_float_rounding_mode(base_fpst);       \
         set_float_rounding_mode(rmode, base_fpst);                      \
         for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {              \
@@ -XXX,XX +XXX,XX @@ void HELPER(mve_vcvtt_hs)(CPUARMState *env, void *vd, void *vm)
             if ((mask & MAKE_64BIT_MASK(0, ESIZE)) == 0) {              \
                 continue;                                               \
             }                                                           \
-            fpst = (ESIZE == 2) ? &env->vfp.fp_status[FPST_STD_F16] :   \
-                &env->vfp.fp_status[FPST_STD];                           \
+            fpst = &env->vfp.fp_status[ESIZE == 2 ? FPST_STD_F16 : FPST_STD]; \
             if (!(mask & 1)) {                                          \
                 /* We need the result but without updating flags */     \
                 scratch_fpst = *fpst;                                   \
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Pass ARMFPStatusFlavour index instead of fp_status[FOO].

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250129013857.135256-17-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/vfp_helper.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -XXX,XX +XXX,XX @@ static void softfloat_to_vfp_compare(CPUARMState *env, FloatRelation cmp)
 void VFP_HELPER(cmp, P)(ARGTYPE a, ARGTYPE b, CPUARMState *env)  \
 { \
     softfloat_to_vfp_compare(env, \
-        FLOATTYPE ## _compare_quiet(a, b, &env->vfp.FPST)); \
+        FLOATTYPE ## _compare_quiet(a, b, &env->vfp.fp_status[FPST])); \
 } \
 void VFP_HELPER(cmpe, P)(ARGTYPE a, ARGTYPE b, CPUARMState *env) \
 { \
     softfloat_to_vfp_compare(env, \
-        FLOATTYPE ## _compare(a, b, &env->vfp.FPST)); \
+        FLOATTYPE ## _compare(a, b, &env->vfp.fp_status[FPST])); \
 }
-DO_VFP_cmp(h, float16, dh_ctype_f16, fp_status[FPST_A32_F16])
-DO_VFP_cmp(s, float32, float32, fp_status[FPST_A32])
-DO_VFP_cmp(d, float64, float64, fp_status[FPST_A32])
+DO_VFP_cmp(h, float16, dh_ctype_f16, FPST_A32_F16)
+DO_VFP_cmp(s, float32, float32, FPST_A32)
+DO_VFP_cmp(d, float64, float64, FPST_A32)
 #undef DO_VFP_cmp
 
 /* Integer to float and float to integer conversions */
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Read the bit from the source, rather than from the proxy via
get_flush_inputs_to_zero.  This makes it clear that it does
not matter which of the float_status structures is used.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-34-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/vec_helper.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index XXXXXXX..XXXXXXX 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_a32)(void *vd, void *vn, void *vm,
     uint64_t negx = is_s ? 0x8000800080008000ull : 0;
 
     do_fmlal(vd, vn, vm, &env->vfp.fp_status[FPST_STD], negx, 0, desc,
-             get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A32_F16]));
+             env->vfp.fpcr & FPCR_FZ16);
 }
 
 void HELPER(gvec_fmlal_a64)(void *vd, void *vn, void *vm,
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_a64)(void *vd, void *vn, void *vm,
         }
     }
     do_fmlal(vd, vn, vm, &env->vfp.fp_status[FPST_A64], negx, negf, desc,
-             get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A64_F16]));
+             env->vfp.fpcr & FPCR_FZ16);
 }
 
 void HELPER(sve2_fmlal_zzzw_s)(void *vd, void *vn, void *vm, void *va,
@@ -XXX,XX +XXX,XX @@ void HELPER(sve2_fmlal_zzzw_s)(void *vd, void *vn, void *vm, void *va,
     bool is_s = extract32(desc, SIMD_DATA_SHIFT, 1);
     intptr_t sel = extract32(desc, SIMD_DATA_SHIFT + 1, 1) * sizeof(float16);
     float_status *status = &env->vfp.fp_status[FPST_A64];
-    bool fz16 = get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A64_F16]);
+    bool fz16 = env->vfp.fpcr & FPCR_FZ16;
     int negx = 0, negf = 0;
 
     if (is_s) {
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_idx_a32)(void *vd, void *vn, void *vm,
     uint64_t negx = is_s ? 0x8000800080008000ull : 0;
 
     do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status[FPST_STD], negx, 0, desc,
-                 get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A32_F16]));
+                 env->vfp.fpcr & FPCR_FZ16);
 }
 
 void HELPER(gvec_fmlal_idx_a64)(void *vd, void *vn, void *vm,
@@ -XXX,XX +XXX,XX @@ void HELPER(gvec_fmlal_idx_a64)(void *vd, void *vn, void *vm,
         }
     }
     do_fmlal_idx(vd, vn, vm, &env->vfp.fp_status[FPST_A64], negx, negf, desc,
-                 get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A64_F16]));
+                 env->vfp.fpcr & FPCR_FZ16);
 }
 
 void HELPER(sve2_fmlal_zzxw_s)(void *vd, void *vn, void *vm, void *va,
@@ -XXX,XX +XXX,XX @@ void HELPER(sve2_fmlal_zzxw_s)(void *vd, void *vn, void *vm, void *va,
     intptr_t sel = extract32(desc, SIMD_DATA_SHIFT + 1, 1) * sizeof(float16);
     intptr_t idx = extract32(desc, SIMD_DATA_SHIFT + 2, 3) * sizeof(float16);
     float_status *status = &env->vfp.fp_status[FPST_A64];
-    bool fz16 = get_flush_inputs_to_zero(&env->vfp.fp_status[FPST_A64_F16]);
+    bool fz16 = env->vfp.fpcr & FPCR_FZ16;
     int negx = 0, negf = 0;
 
     if (is_s) {
-- 
2.34.1

From: Richard Henderson <richard.henderson@linaro.org>

Sink common code from the callers into do_fmlal
and do_fmlal_idx.  Reorder the arguments to minimize
the re-sorting from the caller's arguments.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250129013857.135256-35-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/vec_helper.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

v3->v4: Windows headers define an INT type which clashed
with an enum value name in arm_gicv3_its.c...

The following changes since commit eae587e8e3694b1aceab23239493fb4c7e1a80f5:

Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2021-09-13' into staging (2021-09-13 11:00:30 +0100)

are available in the Git repository at:

https://git.linaro.org/people/pmaydell/qemu-arm.git tags/pull-target-arm-20210913-3

for you to fetch changes up to 28e987a7e7edaa3ca7feeac65edca26145df8814:

hw/arm/mps2.c: Mark internal-only I2C buses as 'full' (2021-09-13 21:01:08 +0100)

----------------------------------------------------------------
target-arm queue:
 * mark MPS2/MPS3 board-internal i2c buses as 'full' so that command
   line user-created devices are not plugged into them
 * Take an exception if PSTATE.IL is set
 * Support an emulated ITS in the virt board
 * Add support for kudo-bmc board
 * Probe for KVM_CAP_ARM_VM_IPA_SIZE when creating scratch VM
 * cadence_uart: Fix clock handling issues that prevented
   u-boot from running

----------------------------------------------------------------
Bin Meng (6):
      hw/misc: zynq_slcr: Correctly compute output clocks in the reset exit phase
      hw/char: cadence_uart: Disable transmit when input clock is disabled
      hw/char: cadence_uart: Move clock/reset check to uart_can_receive()
      hw/char: cadence_uart: Convert to memop_with_attrs() ops
      hw/char: cadence_uart: Ignore access when unclocked or in reset for uart_{read, write}()
      hw/char: cadence_uart: Log a guest error when device is unclocked or in reset

Chris Rauer (1):
      hw/arm: Add support for kudo-bmc board.

Marc Zyngier (1):
      hw/arm/virt: KVM: Probe for KVM_CAP_ARM_VM_IPA_SIZE when creating scratch VM

Peter Maydell (5):
      target/arm: Take an exception if PSTATE.IL is set
      qdev: Support marking individual buses as 'full'
      hw/arm/mps2-tz.c: Add extra data parameter to MakeDevFn
      hw/arm/mps2-tz.c: Mark internal-only I2C buses as 'full'
      hw/arm/mps2.c: Mark internal-only I2C buses as 'full'

Richard Henderson (1):
      target/arm: Merge disas_a64_insn into aarch64_tr_translate_insn

Shashi Mallela (9):
      hw/intc: GICv3 ITS initial framework
      hw/intc: GICv3 ITS register definitions added
      hw/intc: GICv3 ITS command queue framework
      hw/intc: GICv3 ITS Command processing
      hw/intc: GICv3 ITS Feature enablement
      hw/intc: GICv3 redistributor ITS processing
      tests/data/acpi/virt: Add IORT files for ITS
      hw/arm/virt: add ITS support in virt GIC
      tests/data/acpi/virt: Update IORT files for ITS