target/arm: Add BFMLA, BFMLS (indexed)

FEAT_SVE_B16B16 adds bfloat16 versions of the FMLA and FMLS insns in
the SVE floating-point multiply-add (indexed) insn group.  Implement
these.

Fixes: 7b1613a102 ("target/arm: Enable FEAT_SME2p1 on -cpu max")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250718173032.2498900-7-peter.maydell@linaro.org

target/arm/tcg/sve.decode

@@ -1052,9 +1052,11 @@ FCMLA_zzxz      01100100 11 1 index:1 rm:4 0001 rot:2 rn:5 rd:5 \
 ### SVE FP Multiply-Add Indexed Group
 
 # SVE floating-point multiply-add (indexed)
+FMLA_zzxz       01100100 0. 1 ..... 000010 ..... .....  @rrxr_3 esz=0
 FMLA_zzxz       01100100 0. 1 ..... 000000 ..... .....  @rrxr_3 esz=1
 FMLA_zzxz       01100100 10 1 ..... 000000 ..... .....  @rrxr_2 esz=2
 FMLA_zzxz       01100100 11 1 ..... 000000 ..... .....  @rrxr_1 esz=3
+FMLS_zzxz       01100100 0. 1 ..... 000011 ..... .....  @rrxr_3 esz=0
 FMLS_zzxz       01100100 0. 1 ..... 000001 ..... .....  @rrxr_3 esz=1
 FMLS_zzxz       01100100 10 1 ..... 000001 ..... .....  @rrxr_2 esz=2
 FMLS_zzxz       01100100 11 1 ..... 000001 ..... .....  @rrxr_1 esz=3

target/arm/tcg/translate-sve.c

@@ -3883,24 +3883,31 @@ 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,
+                         gen_helper_gvec_4_ptr *fn)
+{
+    /* These insns use MO_8 to encode BFloat16 */
+    if (a->esz == MO_8 && !dc_isar_feature(aa64_sve_b16b16, s)) {
+        return false;
+    }
+    return gen_gvec_fpst_zzzz(s, fn, a->rd, a->rn, a->rm, a->ra, a->index,
+                              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_bfmla_idx, 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, fmla_idx_fns[a->esz])
 
 static gen_helper_gvec_4_ptr * const fmls_idx_fns[4][2] = {
-    { NULL, NULL },
+    { gen_helper_gvec_bfmls_idx, gen_helper_gvec_ah_bfmls_idx },
     { 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)
+TRANS_FEAT(FMLS_zzxz, aa64_sve, do_fmla_zzxz, a,
+           fmls_idx_fns[a->esz][s->fpcr_ah])
 
 /*
  *** SVE Floating Point Multiply Indexed Group