Rename to parts$N_minmax. Combine 3 bool arguments to a bitmask,
return a tri-state value to indicate nan vs unchanged operand.
Introduce ftype_minmax functions as a common optimization point.
Fold bfloat16 expansions into the same macro as the other types.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
fpu/softfloat.c | 216 ++++++++++++++++----------------------
fpu/softfloat-parts.c.inc | 81 ++++++++++++++
2 files changed, 170 insertions(+), 127 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index db14bd09aa..2dadded0b5 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -482,6 +482,15 @@ enum {
float_cmask_anynan = float_cmask_qnan | float_cmask_snan,
};
+/* Flags for parts_minmax. */
+enum {
+ /* Set for minimum; clear for maximum. */
+ minmax_ismin = 1,
+ /* Set for the IEEE 754-2008 minNum() and maxNum() operations. */
+ minmax_isnum = 2,
+ /* Set for the IEEE 754-2008 minNumMag() and minNumMag() operations. */
+ minmax_ismag = 4,
+};
/* Simple helpers for checking if, or what kind of, NaN we have */
static inline __attribute__((unused)) bool is_nan(FloatClass c)
@@ -865,6 +874,14 @@ static void parts128_uint_to_float(FloatParts128 *p, uint64_t a,
#define parts_uint_to_float(P, I, Z, S) \
PARTS_GENERIC_64_128(uint_to_float, P)(P, I, Z, S)
+static int parts64_minmax(FloatParts64 *a, FloatParts64 *b,
+ float_status *s, int flags, const FloatFmt *fmt);
+static int parts128_minmax(FloatParts128 *a, FloatParts128 *b,
+ float_status *s, int flags, const FloatFmt *fmt);
+
+#define parts_minmax(A, B, S, Z, F) \
+ PARTS_GENERIC_64_128(minmax, A)(A, B, S, Z, F)
+
/*
* Helper functions for softfloat-parts.c.inc, per-size operations.
*/
@@ -3258,145 +3275,90 @@ float128 uint64_to_float128(uint64_t a, float_status *status)
return float128_round_pack_canonical(&p, status);
}
-/* Float Min/Max */
-/* min() and max() functions. These can't be implemented as
- * 'compare and pick one input' because that would mishandle
- * NaNs and +0 vs -0.
- *
- * minnum() and maxnum() functions. These are similar to the min()
- * and max() functions but if one of the arguments is a QNaN and
- * the other is numerical then the numerical argument is returned.
- * SNaNs will get quietened before being returned.
- * minnum() and maxnum correspond to the IEEE 754-2008 minNum()
- * and maxNum() operations. min() and max() are the typical min/max
- * semantics provided by many CPUs which predate that specification.
- *
- * minnummag() and maxnummag() functions correspond to minNumMag()
- * and minNumMag() from the IEEE-754 2008.
+/*
+ * Minimum and maximum
*/
-static FloatParts64 minmax_floats(FloatParts64 a, FloatParts64 b, bool ismin,
- bool ieee, bool ismag, float_status *s)
+
+static float16 float16_minmax(float16 a, float16 b, float_status *s, int flags)
{
- if (unlikely(is_nan(a.cls) || is_nan(b.cls))) {
- if (ieee) {
- /* Takes two floating-point values `a' and `b', one of
- * which is a NaN, and returns the appropriate NaN
- * result. If either `a' or `b' is a signaling NaN,
- * the invalid exception is raised.
- */
- if (is_snan(a.cls) || is_snan(b.cls)) {
- return *parts_pick_nan(&a, &b, s);
- } else if (is_nan(a.cls) && !is_nan(b.cls)) {
- return b;
- } else if (is_nan(b.cls) && !is_nan(a.cls)) {
- return a;
- }
- }
- return *parts_pick_nan(&a, &b, s);
- } else {
- int a_exp, b_exp;
+ FloatParts64 pa, pb;
+ int which;
- switch (a.cls) {
- case float_class_normal:
- a_exp = a.exp;
- break;
- case float_class_inf:
- a_exp = INT_MAX;
- break;
- case float_class_zero:
- a_exp = INT_MIN;
- break;
- default:
- g_assert_not_reached();
- break;
- }
- switch (b.cls) {
- case float_class_normal:
- b_exp = b.exp;
- break;
- case float_class_inf:
- b_exp = INT_MAX;
- break;
- case float_class_zero:
- b_exp = INT_MIN;
- break;
- default:
- g_assert_not_reached();
- break;
- }
-
- if (ismag && (a_exp != b_exp || a.frac != b.frac)) {
- bool a_less = a_exp < b_exp;
- if (a_exp == b_exp) {
- a_less = a.frac < b.frac;
- }
- return a_less ^ ismin ? b : a;
- }
-
- if (a.sign == b.sign) {
- bool a_less = a_exp < b_exp;
- if (a_exp == b_exp) {
- a_less = a.frac < b.frac;
- }
- return a.sign ^ a_less ^ ismin ? b : a;
- } else {
- return a.sign ^ ismin ? b : a;
- }
+ float16_unpack_canonical(&pa, a, s);
+ float16_unpack_canonical(&pb, b, s);
+ which = parts_minmax(&pa, &pb, s, flags, &float16_params);
+ if (unlikely(which < 0)) {
+ /* Some sort of nan, need to repack default and silenced nans. */
+ return float16_round_pack_canonical(&pa, s);
}
+ return which ? b : a;
}
-#define MINMAX(sz, name, ismin, isiee, ismag) \
-float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \
- float_status *s) \
-{ \
- FloatParts64 pa, pb, pr; \
- float ## sz ## _unpack_canonical(&pa, a, s); \
- float ## sz ## _unpack_canonical(&pb, b, s); \
- pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
- return float ## sz ## _round_pack_canonical(&pr, s); \
+static bfloat16 bfloat16_minmax(bfloat16 a, bfloat16 b,
+ float_status *s, int flags)
+{
+ FloatParts64 pa, pb;
+ int which;
+
+ bfloat16_unpack_canonical(&pa, a, s);
+ bfloat16_unpack_canonical(&pb, b, s);
+ which = parts_minmax(&pa, &pb, s, flags, &float16_params);
+ if (unlikely(which < 0)) {
+ /* Some sort of nan, need to repack default and silenced nans. */
+ return bfloat16_round_pack_canonical(&pa, s);
+ }
+ return which ? b : a;
}
-MINMAX(16, min, true, false, false)
-MINMAX(16, minnum, true, true, false)
-MINMAX(16, minnummag, true, true, true)
-MINMAX(16, max, false, false, false)
-MINMAX(16, maxnum, false, true, false)
-MINMAX(16, maxnummag, false, true, true)
+static float32 float32_minmax(float32 a, float32 b, float_status *s, int flags)
+{
+ FloatParts64 pa, pb;
+ int which;
-MINMAX(32, min, true, false, false)
-MINMAX(32, minnum, true, true, false)
-MINMAX(32, minnummag, true, true, true)
-MINMAX(32, max, false, false, false)
-MINMAX(32, maxnum, false, true, false)
-MINMAX(32, maxnummag, false, true, true)
-
-MINMAX(64, min, true, false, false)
-MINMAX(64, minnum, true, true, false)
-MINMAX(64, minnummag, true, true, true)
-MINMAX(64, max, false, false, false)
-MINMAX(64, maxnum, false, true, false)
-MINMAX(64, maxnummag, false, true, true)
-
-#undef MINMAX
-
-#define BF16_MINMAX(name, ismin, isiee, ismag) \
-bfloat16 bfloat16_ ## name(bfloat16 a, bfloat16 b, float_status *s) \
-{ \
- FloatParts64 pa, pb, pr; \
- bfloat16_unpack_canonical(&pa, a, s); \
- bfloat16_unpack_canonical(&pb, b, s); \
- pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
- return bfloat16_round_pack_canonical(&pr, s); \
+ float32_unpack_canonical(&pa, a, s);
+ float32_unpack_canonical(&pb, b, s);
+ which = parts_minmax(&pa, &pb, s, flags, &float32_params);
+ if (unlikely(which < 0)) {
+ /* Some sort of nan, need to repack default and silenced nans. */
+ return float32_round_pack_canonical(&pa, s);
+ }
+ return which ? b : a;
}
-BF16_MINMAX(min, true, false, false)
-BF16_MINMAX(minnum, true, true, false)
-BF16_MINMAX(minnummag, true, true, true)
-BF16_MINMAX(max, false, false, false)
-BF16_MINMAX(maxnum, false, true, false)
-BF16_MINMAX(maxnummag, false, true, true)
+static float64 float64_minmax(float64 a, float64 b, float_status *s, int flags)
+{
+ FloatParts64 pa, pb;
+ int which;
-#undef BF16_MINMAX
+ float64_unpack_canonical(&pa, a, s);
+ float64_unpack_canonical(&pb, b, s);
+ which = parts_minmax(&pa, &pb, s, flags, &float64_params);
+ if (unlikely(which < 0)) {
+ /* Some sort of nan, need to repack default and silenced nans. */
+ return float64_round_pack_canonical(&pa, s);
+ }
+ return which ? b : a;
+}
+
+#define MINMAX_1(type, name, flags) \
+ type type##_##name(type a, type b, float_status *s) \
+ { return type##_minmax(a, b, s, flags); }
+
+#define MINMAX_2(type) \
+ MINMAX_1(type, max, 0) \
+ MINMAX_1(type, maxnum, minmax_isnum) \
+ MINMAX_1(type, maxnummag, minmax_isnum | minmax_ismag) \
+ MINMAX_1(type, min, minmax_ismin) \
+ MINMAX_1(type, minnum, minmax_ismin | minmax_isnum) \
+ MINMAX_1(type, minnummag, minmax_ismin | minmax_isnum | minmax_ismag)
+
+MINMAX_2(float16)
+MINMAX_2(bfloat16)
+MINMAX_2(float32)
+MINMAX_2(float64)
+
+#undef MINMAX_1
+#undef MINMAX_2
/* Floating point compare */
static FloatRelation compare_floats(FloatParts64 a, FloatParts64 b, bool is_quiet,
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index f3c4f8c8d2..d68ab8fee0 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -936,3 +936,84 @@ static void partsN(uint_to_float)(FloatPartsN *p, uint64_t a,
p->frac_hi = a << shift;
}
}
+
+/*
+ * Float min/max.
+ *
+ * Return -1 to return the chosen nan in *a;
+ * return 0 to use the a input unchanged; 1 to use the b input unchanged.
+ */
+static int partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
+ float_status *s, int flags, const FloatFmt *fmt)
+{
+ int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
+ int a_exp, b_exp, cmp;
+
+ if (unlikely(ab_mask & float_cmask_anynan)) {
+ /*
+ * For minnum/maxnum, if one operand is a QNaN, and the other
+ * operand is numerical, then return numerical argument.
+ */
+ if ((flags & minmax_isnum)
+ && !(ab_mask & float_cmask_snan)
+ && (ab_mask & ~float_cmask_qnan)) {
+ return is_nan(a->cls);
+ }
+ *a = *parts_pick_nan(a, b, s);
+ return -1;
+ }
+
+ a_exp = a->exp;
+ b_exp = b->exp;
+
+ if (unlikely(ab_mask != float_cmask_normal)) {
+ switch (a->cls) {
+ case float_class_normal:
+ break;
+ case float_class_inf:
+ a_exp = INT16_MAX;
+ break;
+ case float_class_zero:
+ a_exp = INT16_MIN;
+ break;
+ default:
+ g_assert_not_reached();
+ break;
+ }
+ switch (b->cls) {
+ case float_class_normal:
+ break;
+ case float_class_inf:
+ b_exp = INT16_MAX;
+ break;
+ case float_class_zero:
+ b_exp = INT16_MIN;
+ break;
+ default:
+ g_assert_not_reached();
+ break;
+ }
+ }
+
+ /* Compare magnitudes. */
+ cmp = a_exp - b_exp;
+ if (cmp == 0) {
+ cmp = frac_cmp(a, b);
+ }
+
+ /*
+ * Take the sign into account.
+ * For ismag, only do this if the magnitudes are equal.
+ */
+ if (!(flags & minmax_ismag) || cmp == 0) {
+ if (a->sign != b->sign) {
+ /* For differing signs, the negative operand is less. */
+ cmp = a->sign ? -1 : 1;
+ } else if (a->sign) {
+ /* For two negative operands, invert the magnitude comparison. */
+ cmp = -cmp;
+ }
+ }
+
+ return (cmp < 0) ^ !!(flags & minmax_ismin);
+}
--
2.25.1
On 25.05.21 17:06, Richard Henderson wrote:
> Rename to parts$N_minmax. Combine 3 bool arguments to a bitmask,
> return a tri-state value to indicate nan vs unchanged operand.
> Introduce ftype_minmax functions as a common optimization point.
> Fold bfloat16 expansions into the same macro as the other types.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> fpu/softfloat.c | 216 ++++++++++++++++----------------------
> fpu/softfloat-parts.c.inc | 81 ++++++++++++++
> 2 files changed, 170 insertions(+), 127 deletions(-)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index db14bd09aa..2dadded0b5 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -482,6 +482,15 @@ enum {
> float_cmask_anynan = float_cmask_qnan | float_cmask_snan,
> };
>
> +/* Flags for parts_minmax. */
> +enum {
> + /* Set for minimum; clear for maximum. */
> + minmax_ismin = 1,
> + /* Set for the IEEE 754-2008 minNum() and maxNum() operations. */
> + minmax_isnum = 2,
> + /* Set for the IEEE 754-2008 minNumMag() and minNumMag() operations. */
> + minmax_ismag = 4,
> +};
>
> /* Simple helpers for checking if, or what kind of, NaN we have */
> static inline __attribute__((unused)) bool is_nan(FloatClass c)
> @@ -865,6 +874,14 @@ static void parts128_uint_to_float(FloatParts128 *p, uint64_t a,
> #define parts_uint_to_float(P, I, Z, S) \
> PARTS_GENERIC_64_128(uint_to_float, P)(P, I, Z, S)
>
> +static int parts64_minmax(FloatParts64 *a, FloatParts64 *b,
> + float_status *s, int flags, const FloatFmt *fmt);
> +static int parts128_minmax(FloatParts128 *a, FloatParts128 *b,
> + float_status *s, int flags, const FloatFmt *fmt);
> +
> +#define parts_minmax(A, B, S, Z, F) \
> + PARTS_GENERIC_64_128(minmax, A)(A, B, S, Z, F)
> +
> /*
> * Helper functions for softfloat-parts.c.inc, per-size operations.
> */
> @@ -3258,145 +3275,90 @@ float128 uint64_to_float128(uint64_t a, float_status *status)
> return float128_round_pack_canonical(&p, status);
> }
>
> -/* Float Min/Max */
> -/* min() and max() functions. These can't be implemented as
> - * 'compare and pick one input' because that would mishandle
> - * NaNs and +0 vs -0.
> - *
> - * minnum() and maxnum() functions. These are similar to the min()
> - * and max() functions but if one of the arguments is a QNaN and
> - * the other is numerical then the numerical argument is returned.
> - * SNaNs will get quietened before being returned.
> - * minnum() and maxnum correspond to the IEEE 754-2008 minNum()
> - * and maxNum() operations. min() and max() are the typical min/max
> - * semantics provided by many CPUs which predate that specification.
> - *
> - * minnummag() and maxnummag() functions correspond to minNumMag()
> - * and minNumMag() from the IEEE-754 2008.
> +/*
> + * Minimum and maximum
> */
> -static FloatParts64 minmax_floats(FloatParts64 a, FloatParts64 b, bool ismin,
> - bool ieee, bool ismag, float_status *s)
> +
> +static float16 float16_minmax(float16 a, float16 b, float_status *s, int flags)
> {
> - if (unlikely(is_nan(a.cls) || is_nan(b.cls))) {
> - if (ieee) {
> - /* Takes two floating-point values `a' and `b', one of
> - * which is a NaN, and returns the appropriate NaN
> - * result. If either `a' or `b' is a signaling NaN,
> - * the invalid exception is raised.
> - */
> - if (is_snan(a.cls) || is_snan(b.cls)) {
> - return *parts_pick_nan(&a, &b, s);
> - } else if (is_nan(a.cls) && !is_nan(b.cls)) {
> - return b;
> - } else if (is_nan(b.cls) && !is_nan(a.cls)) {
> - return a;
> - }
> - }
> - return *parts_pick_nan(&a, &b, s);
> - } else {
> - int a_exp, b_exp;
> + FloatParts64 pa, pb;
> + int which;
>
> - switch (a.cls) {
> - case float_class_normal:
> - a_exp = a.exp;
> - break;
> - case float_class_inf:
> - a_exp = INT_MAX;
> - break;
> - case float_class_zero:
> - a_exp = INT_MIN;
> - break;
> - default:
> - g_assert_not_reached();
> - break;
> - }
> - switch (b.cls) {
> - case float_class_normal:
> - b_exp = b.exp;
> - break;
> - case float_class_inf:
> - b_exp = INT_MAX;
> - break;
> - case float_class_zero:
> - b_exp = INT_MIN;
> - break;
> - default:
> - g_assert_not_reached();
> - break;
> - }
> -
> - if (ismag && (a_exp != b_exp || a.frac != b.frac)) {
> - bool a_less = a_exp < b_exp;
> - if (a_exp == b_exp) {
> - a_less = a.frac < b.frac;
> - }
> - return a_less ^ ismin ? b : a;
> - }
> -
> - if (a.sign == b.sign) {
> - bool a_less = a_exp < b_exp;
> - if (a_exp == b_exp) {
> - a_less = a.frac < b.frac;
> - }
> - return a.sign ^ a_less ^ ismin ? b : a;
> - } else {
> - return a.sign ^ ismin ? b : a;
> - }
> + float16_unpack_canonical(&pa, a, s);
> + float16_unpack_canonical(&pb, b, s);
> + which = parts_minmax(&pa, &pb, s, flags, &float16_params);
> + if (unlikely(which < 0)) {
> + /* Some sort of nan, need to repack default and silenced nans. */
> + return float16_round_pack_canonical(&pa, s);
> }
> + return which ? b : a;
> }
>
> -#define MINMAX(sz, name, ismin, isiee, ismag) \
> -float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \
> - float_status *s) \
> -{ \
> - FloatParts64 pa, pb, pr; \
> - float ## sz ## _unpack_canonical(&pa, a, s); \
> - float ## sz ## _unpack_canonical(&pb, b, s); \
> - pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
> - return float ## sz ## _round_pack_canonical(&pr, s); \
> +static bfloat16 bfloat16_minmax(bfloat16 a, bfloat16 b,
> + float_status *s, int flags)
> +{
> + FloatParts64 pa, pb;
> + int which;
> +
> + bfloat16_unpack_canonical(&pa, a, s);
> + bfloat16_unpack_canonical(&pb, b, s);
> + which = parts_minmax(&pa, &pb, s, flags, &float16_params);
> + if (unlikely(which < 0)) {
> + /* Some sort of nan, need to repack default and silenced nans. */
> + return bfloat16_round_pack_canonical(&pa, s);
> + }
> + return which ? b : a;
> }
>
> -MINMAX(16, min, true, false, false)
> -MINMAX(16, minnum, true, true, false)
> -MINMAX(16, minnummag, true, true, true)
> -MINMAX(16, max, false, false, false)
> -MINMAX(16, maxnum, false, true, false)
> -MINMAX(16, maxnummag, false, true, true)
> +static float32 float32_minmax(float32 a, float32 b, float_status *s, int flags)
> +{
> + FloatParts64 pa, pb;
> + int which;
>
> -MINMAX(32, min, true, false, false)
> -MINMAX(32, minnum, true, true, false)
> -MINMAX(32, minnummag, true, true, true)
> -MINMAX(32, max, false, false, false)
> -MINMAX(32, maxnum, false, true, false)
> -MINMAX(32, maxnummag, false, true, true)
> -
> -MINMAX(64, min, true, false, false)
> -MINMAX(64, minnum, true, true, false)
> -MINMAX(64, minnummag, true, true, true)
> -MINMAX(64, max, false, false, false)
> -MINMAX(64, maxnum, false, true, false)
> -MINMAX(64, maxnummag, false, true, true)
> -
> -#undef MINMAX
> -
> -#define BF16_MINMAX(name, ismin, isiee, ismag) \
> -bfloat16 bfloat16_ ## name(bfloat16 a, bfloat16 b, float_status *s) \
> -{ \
> - FloatParts64 pa, pb, pr; \
> - bfloat16_unpack_canonical(&pa, a, s); \
> - bfloat16_unpack_canonical(&pb, b, s); \
> - pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
> - return bfloat16_round_pack_canonical(&pr, s); \
> + float32_unpack_canonical(&pa, a, s);
> + float32_unpack_canonical(&pb, b, s);
> + which = parts_minmax(&pa, &pb, s, flags, &float32_params);
> + if (unlikely(which < 0)) {
> + /* Some sort of nan, need to repack default and silenced nans. */
> + return float32_round_pack_canonical(&pa, s);
> + }
> + return which ? b : a;
> }
>
> -BF16_MINMAX(min, true, false, false)
> -BF16_MINMAX(minnum, true, true, false)
> -BF16_MINMAX(minnummag, true, true, true)
> -BF16_MINMAX(max, false, false, false)
> -BF16_MINMAX(maxnum, false, true, false)
> -BF16_MINMAX(maxnummag, false, true, true)
> +static float64 float64_minmax(float64 a, float64 b, float_status *s, int flags)
> +{
> + FloatParts64 pa, pb;
> + int which;
>
> -#undef BF16_MINMAX
> + float64_unpack_canonical(&pa, a, s);
> + float64_unpack_canonical(&pb, b, s);
> + which = parts_minmax(&pa, &pb, s, flags, &float64_params);
> + if (unlikely(which < 0)) {
> + /* Some sort of nan, need to repack default and silenced nans. */
> + return float64_round_pack_canonical(&pa, s);
> + }
> + return which ? b : a;
> +}
> +
> +#define MINMAX_1(type, name, flags) \
> + type type##_##name(type a, type b, float_status *s) \
> + { return type##_minmax(a, b, s, flags); }
> +
> +#define MINMAX_2(type) \
> + MINMAX_1(type, max, 0) \
> + MINMAX_1(type, maxnum, minmax_isnum) \
> + MINMAX_1(type, maxnummag, minmax_isnum | minmax_ismag) \
> + MINMAX_1(type, min, minmax_ismin) \
> + MINMAX_1(type, minnum, minmax_ismin | minmax_isnum) \
> + MINMAX_1(type, minnummag, minmax_ismin | minmax_isnum | minmax_ismag)
> +
> +MINMAX_2(float16)
> +MINMAX_2(bfloat16)
> +MINMAX_2(float32)
> +MINMAX_2(float64)
> +
> +#undef MINMAX_1
> +#undef MINMAX_2
>
> /* Floating point compare */
> static FloatRelation compare_floats(FloatParts64 a, FloatParts64 b, bool is_quiet,
> diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
> index f3c4f8c8d2..d68ab8fee0 100644
> --- a/fpu/softfloat-parts.c.inc
> +++ b/fpu/softfloat-parts.c.inc
> @@ -936,3 +936,84 @@ static void partsN(uint_to_float)(FloatPartsN *p, uint64_t a,
> p->frac_hi = a << shift;
> }
> }
> +
> +/*
> + * Float min/max.
> + *
> + * Return -1 to return the chosen nan in *a;
> + * return 0 to use the a input unchanged; 1 to use the b input unchanged.
> + */
> +static int partsN(minmax)(FloatPartsN *a, FloatPartsN *b,
> + float_status *s, int flags, const FloatFmt *fmt)
> +{
> + int ab_mask = float_cmask(a->cls) | float_cmask(b->cls);
> + int a_exp, b_exp, cmp;
> +
> + if (unlikely(ab_mask & float_cmask_anynan)) {
> + /*
> + * For minnum/maxnum, if one operand is a QNaN, and the other
> + * operand is numerical, then return numerical argument.
> + */
> + if ((flags & minmax_isnum)
> + && !(ab_mask & float_cmask_snan)
> + && (ab_mask & ~float_cmask_qnan)) {
> + return is_nan(a->cls);
> + }
> + *a = *parts_pick_nan(a, b, s);
> + return -1;
> + }
> +
> + a_exp = a->exp;
> + b_exp = b->exp;
> +
> + if (unlikely(ab_mask != float_cmask_normal)) {
> + switch (a->cls) {
> + case float_class_normal:
> + break;
> + case float_class_inf:
> + a_exp = INT16_MAX;
> + break;
> + case float_class_zero:
> + a_exp = INT16_MIN;
> + break;
> + default:
> + g_assert_not_reached();
> + break;
> + }
> + switch (b->cls) {
> + case float_class_normal:
> + break;
> + case float_class_inf:
> + b_exp = INT16_MAX;
> + break;
> + case float_class_zero:
> + b_exp = INT16_MIN;
> + break;
> + default:
> + g_assert_not_reached();
> + break;
> + }
> + }
> +
> + /* Compare magnitudes. */
> + cmp = a_exp - b_exp;
> + if (cmp == 0) {
> + cmp = frac_cmp(a, b);
> + }
> +
> + /*
> + * Take the sign into account.
> + * For ismag, only do this if the magnitudes are equal.
> + */
> + if (!(flags & minmax_ismag) || cmp == 0) {
> + if (a->sign != b->sign) {
> + /* For differing signs, the negative operand is less. */
> + cmp = a->sign ? -1 : 1;
> + } else if (a->sign) {
> + /* For two negative operands, invert the magnitude comparison. */
> + cmp = -cmp;
> + }
> + }
> +
> + return (cmp < 0) ^ !!(flags & minmax_ismin);
> +}
>
Looks good to me
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
Richard Henderson <richard.henderson@linaro.org> writes:
> Rename to parts$N_minmax. Combine 3 bool arguments to a bitmask,
> return a tri-state value to indicate nan vs unchanged operand.
> Introduce ftype_minmax functions as a common optimization point.
> Fold bfloat16 expansions into the same macro as the other types.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
<snip>
> - switch (a.cls) {
> - case float_class_normal:
> - a_exp = a.exp;
> - break;
> - case float_class_inf:
> - a_exp = INT_MAX;
> - break;
> - case float_class_zero:
> - a_exp = INT_MIN;
> - break;
> - default:
> - g_assert_not_reached();
> - break;
> - }
> - switch (b.cls) {
> - case float_class_normal:
> - b_exp = b.exp;
> - break;
> - case float_class_inf:
> - b_exp = INT_MAX;
> - break;
> - case float_class_zero:
> - b_exp = INT_MIN;
> - break;
> - default:
> - g_assert_not_reached();
> - break;
> - }
> -
<snip>
> + if (unlikely(ab_mask != float_cmask_normal)) {
> + switch (a->cls) {
> + case float_class_normal:
> + break;
> + case float_class_inf:
> + a_exp = INT16_MAX;
We've gone from min/max of our internal representation to INT16_MIN/MAX
- I guess that doesn't break until we get to Float256 but why the change?
--
Alex Bennée
On 6/2/21 1:36 PM, Alex Bennée wrote:
>
> Richard Henderson <richard.henderson@linaro.org> writes:
>
>> Rename to parts$N_minmax. Combine 3 bool arguments to a bitmask,
>> return a tri-state value to indicate nan vs unchanged operand.
>> Introduce ftype_minmax functions as a common optimization point.
>> Fold bfloat16 expansions into the same macro as the other types.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
> <snip>
>> - switch (a.cls) {
>> - case float_class_normal:
>> - a_exp = a.exp;
>> - break;
>> - case float_class_inf:
>> - a_exp = INT_MAX;
>> - break;
>> - case float_class_zero:
>> - a_exp = INT_MIN;
>> - break;
>> - default:
>> - g_assert_not_reached();
>> - break;
>> - }
>> - switch (b.cls) {
>> - case float_class_normal:
>> - b_exp = b.exp;
>> - break;
>> - case float_class_inf:
>> - b_exp = INT_MAX;
>> - break;
>> - case float_class_zero:
>> - b_exp = INT_MIN;
>> - break;
>> - default:
>> - g_assert_not_reached();
>> - break;
>> - }
>> -
> <snip>
>> + if (unlikely(ab_mask != float_cmask_normal)) {
>> + switch (a->cls) {
>> + case float_class_normal:
>> + break;
>> + case float_class_inf:
>> + a_exp = INT16_MAX;
>
> We've gone from min/max of our internal representation to INT16_MIN/MAX
> - I guess that doesn't break until we get to Float256 but why the change?
Ah, because I've changed from "bool a_less" to "int cmp". I subtract the two
exponents and I don't want that subtraction to overflow.
r~
On 5/25/21 8:06 AM, Richard Henderson wrote:
> + which = parts_minmax(&pa, &pb, s, flags, &float32_params);
> + if (unlikely(which < 0)) {
> + /* Some sort of nan, need to repack default and silenced nans. */
> + return float32_round_pack_canonical(&pa, s);
> + }
> + return which ? b : a;
I've just realized that if flush_inputs_to_zero is on, then the result should
reflect that rather than returning the denormal.
Will fix.
r~
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