Commit 0c00be3786 for qemu.org

commit 0c00be3786c2b8441d20dd092276100f03deeb75
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Tue Jun 9 12:21:02 2026 -0700

    target/arm: Implement FDOT (FP8 to FP16) for SVE

    Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
    Message-id: 20260609192110.752384-39-richard.henderson@linaro.org
    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h
index caae3e51f3..1745989bce 100644
--- a/target/arm/cpu-features.h
+++ b/target/arm/cpu-features.h
@@ -1580,6 +1580,11 @@ static inline bool isar_feature_aa64_ssve_f8dp4(const ARMISARegisters *id)
     return FIELD_EX64_IDREG(id, ID_AA64SMFR0, SF8DP4);
 }

+static inline bool isar_feature_aa64_ssve_f8dp2(const ARMISARegisters *id)
+{
+    return FIELD_EX64_IDREG(id, ID_AA64SMFR0, SF8DP2);
+}
+
 static inline bool isar_feature_aa64_sme_b16b16(const ARMISARegisters *id)
 {
     return FIELD_EX64_IDREG(id, ID_AA64SMFR0, B16B16);
diff --git a/target/arm/tcg/sve.decode b/target/arm/tcg/sve.decode
index c49e992f10..26b3c7697a 100644
--- a/target/arm/tcg/sve.decode
+++ b/target/arm/tcg/sve.decode
@@ -1875,6 +1875,7 @@ FDOT_zzzz       01100100 00 1 ..... 10 0 00 0 ..... .....  @rda_rn_rm_ex esz=2
 BFDOT_zzzz      01100100 01 1 ..... 10 0 00 0 ..... .....  @rda_rn_rm_ex esz=2

 FDOT_sb         01100100 01 1 ..... 10 0 00 1 ..... .....  @rda_rn_rm_ex esz=2
+FDOT_hb         01100100 00 1 ..... 10 0 00 1 ..... .....  @rda_rn_rm_ex esz=1

 ### SVE2 floating-point multiply-add long (indexed)

@@ -1900,6 +1901,7 @@ FDOT_zzxz       01100100 00 1 ..... 010000 ..... .....     @rrxr_2 esz=2
 BFDOT_zzxz      01100100 01 1 ..... 010000 ..... .....     @rrxr_2 esz=2

 FDOT_idx_sb     01100100 01 1 ..... 010001 ..... .....     @rrxr_2 esz=2
+FDOT_idx_hb     01100100 00 1 ..... 0100.1 ..... .....     @rrx_3a esz=1

 ### SVE broadcast predicate element

diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index 582471b380..2cc5e129e9 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -8426,3 +8426,38 @@ static bool do_f8dp4(DisasContext *s, gen_helper_gvec_3_ptr *fn,
 TRANS(FDOT_sb, do_f8dp4, gen_helper_gvec_fdot_sb, a->rd, a->rn, a->rm, 0)
 TRANS(FDOT_idx_sb, do_f8dp4, gen_helper_gvec_fdot_idx_sb,
       a->rd, a->rn, a->rm, a->index)
+
+static bool do_f8dp2(DisasContext *s, gen_helper_gvec_3_ptr *fn,
+                     int rd, int rn, int rm, int index)
+{
+    bool fp8dp2 = dc_isar_feature(aa64_f8dp2, s);
+    bool ssve_fp8dp2 = dc_isar_feature(aa64_ssve_f8dp2, s);
+    bool ok = false;
+
+    /* Feature detection and enabling are complex here. */
+    if (!(ssve_fp8dp2 || (fp8dp2 && dc_isar_feature(aa64_sve2, s)))) {
+        return false;
+    }
+    if (fpmr_access_check(s)) {
+        if (fp8dp2) {
+            s->is_nonstreaming = !ssve_fp8dp2;
+            ok = sve_access_check(s);
+        } else {
+            ok = sme_sm_enabled_check(s);
+        }
+    }
+
+    if (ok) {
+        unsigned vsz = vec_full_reg_size(s);
+        tcg_gen_gvec_3_ptr(vec_full_reg_offset(s, rd),
+                           vec_full_reg_offset(s, rn),
+                           vec_full_reg_offset(s, rm),
+                           tcg_env, vsz, vsz,
+                           index, fn);
+    }
+    return true;
+}
+
+TRANS(FDOT_hb, do_f8dp2, gen_helper_gvec_fdot_hb, a->rd, a->rn, a->rm, 0)
+TRANS(FDOT_idx_hb, do_f8dp2, gen_helper_gvec_fdot_idx_hb,
+      a->rd, a->rn, a->rm, a->index)