Compare and branch instructions, with various operand widths.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 60 ++++++++++++++++++++++++++++++++++
 target/arm/tcg/a64.decode      |  5 +++
 2 files changed, 65 insertions(+)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 0c78d4bb79..f3970ac599 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1706,6 +1706,66 @@ static bool trans_B_cond(DisasContext *s, arg_B_cond *a)
     return true;
 }
 
+static bool do_cb_cond(DisasContext *s, int cc, int imm,
+                       int rt, int rm, MemOp mop)
+{
+    static const TCGCond cb_cond[8] = {
+        [0] = TCG_COND_GT,
+        [1] = TCG_COND_GE,
+        [2] = TCG_COND_GTU,
+        [3] = TCG_COND_GEU,
+        [4] = TCG_COND_NEVER,  /* reserved */
+        [5] = TCG_COND_NEVER,  /* reserved */
+        [6] = TCG_COND_EQ,
+        [7] = TCG_COND_NE,
+    };
+    TCGCond cond = cb_cond[cc];
+    TCGv_i64 t, m;
+
+    if (!dc_isar_feature(aa64_cmpbr, s) || cond == TCG_COND_NEVER) {
+        return false;
+    }
+
+    t = cpu_reg(s, rt);
+    m = cpu_reg(s, rm);
+    if (mop != MO_64) {
+        TCGv_i64 tt = tcg_temp_new_i64();
+        TCGv_i64 tm = tcg_temp_new_i64();
+
+        if (is_signed_cond(cond)) {
+            mop |= MO_SIGN;
+        }
+        tcg_gen_ext_i64(tt, t, mop);
+        tcg_gen_ext_i64(tm, m, mop);
+        t = tt;
+        m = tm;
+    }
+
+    reset_btype(s);
+    DisasLabel match = gen_disas_label(s);
+
+    tcg_gen_brcond_i64(cond, t, m, match.label);
+    gen_goto_tb(s, 0, 4);
+    set_disas_label(s, match);
+    gen_goto_tb(s, 1, imm);
+    return true;
+}
+
+static bool trans_CB_cond(DisasContext *s, arg_CB_cond *a)
+{
+    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, a->sf ? 64 : 32);
+}
+
+static bool trans_CBB_cond(DisasContext *s, arg_CBB_cond *a)
+{
+    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, 8);
+}
+
+static bool trans_CBH_cond(DisasContext *s, arg_CBH_cond *a)
+{
+    return do_cb_cond(s, a->cc, a->imm, 16, a->rt, a->rm);
+}
+
 static void set_btype_for_br(DisasContext *s, int rn)
 {
     if (dc_isar_feature(aa64_bti, s)) {
diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index 766c610c01..fa94631123 100644
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -208,6 +208,11 @@ TBZ             . 011011 nz:1 ..... .............. rt:5 &tbz  imm=%imm14 bitpos=
 # B.cond and BC.cond
 B_cond          0101010 0 ................... c:1 cond:4 imm=%imm19
 
+%imm9           5:s9   !function=times_4
+CB_cond         sf:1 1110100 cc:3 rm:5 00 ......... rt:5    imm=%imm9
+CBB_cond        0    1110100 cc:3 rm:5 10 ......... rt:5    imm=%imm9
+CBH_cond        0    1110100 cc:3 rm:5 11 ......... rt:5    imm=%imm9
+
 BR              1101011 0000 11111 000000 rn:5 00000 &r
 BLR             1101011 0001 11111 000000 rn:5 00000 &r
 RET             1101011 0010 11111 000000 rn:5 00000 &r
-- 
2.43.0

On 8/3/25 03:40, Richard Henderson wrote:
> +static bool do_cb_cond(DisasContext *s, int cc, int imm,
> +                       int rt, int rm, MemOp mop)

This is a memop...

> +static bool trans_CB_cond(DisasContext *s, arg_CB_cond *a)
> +{
> +    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, a->sf ? 64 : 32);
> +}
> +
> +static bool trans_CBB_cond(DisasContext *s, arg_CBB_cond *a)
> +{
> +    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, 8);
> +}

... but these use bits

> +static bool trans_CBH_cond(DisasContext *s, arg_CBH_cond *a)
> +{
> +    return do_cb_cond(s, a->cc, a->imm, 16, a->rt, a->rm);
> +}
> +

... and this one also has arguments in the wrong order.

Paolo

On 8/3/25 22:31, Paolo Bonzini wrote:
> On 8/3/25 03:40, Richard Henderson wrote:
>> +static bool do_cb_cond(DisasContext *s, int cc, int imm,
>> +                       int rt, int rm, MemOp mop)
> 
> This is a memop...
> 
>> +static bool trans_CB_cond(DisasContext *s, arg_CB_cond *a)
>> +{
>> +    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, a->sf ? 64 : 32);
>> +}
>> +
>> +static bool trans_CBB_cond(DisasContext *s, arg_CBB_cond *a)
>> +{
>> +    return do_cb_cond(s, a->cc, a->imm, a->rt, a->rm, 8);
>> +}
> 
> ... but these use bits
> 
>> +static bool trans_CBH_cond(DisasContext *s, arg_CBH_cond *a)
>> +{
>> +    return do_cb_cond(s, a->cc, a->imm, 16, a->rt, a->rm);
>> +}
>> +
> 
> ... and this one also has arguments in the wrong order.

Gah.  Thanks.  I've reorganized the code to avoid this entirely.

Now to fix a gcc crash when emitting code for cmpbr...  :-)


r~