target/arm: Convert VCMLA (scalar) to decodetree

Convert VCMLA (scalar) in the 2reg-scalar-ext group to decodetree.

Backports commit 7e1b5d615361bb0038cda0e08af41e350e42d081 from qemu

qemu/target/arm/neon-shared.decode

@@ -49,3 +49,8 @@ VFML           1111 110 0 s:1 . 10 .... .... 1000 . 0 . 1 .... \
                vm=%vm_sp vn=%vn_sp vd=%vd_dp q=0
 VFML           1111 110 0 s:1 . 10 .... .... 1000 . 1 . 1 .... \
                vm=%vm_dp vn=%vn_dp vd=%vd_dp q=1
+
+VCMLA_scalar   1111 1110 0 . rot:2 .... .... 1000 . q:1 index:1 0 vm:4 \
+               vn=%vn_dp vd=%vd_dp size=0
+VCMLA_scalar   1111 1110 1 . rot:2 .... .... 1000 . q:1 . 0 .... \
+               vm=%vm_dp vn=%vn_dp vd=%vd_dp size=1 index=0

qemu/target/arm/translate-neon.inc.c

@@ -172,3 +172,43 @@ static bool trans_VFML(DisasContext *s, arg_VFML *a)
     return true;
 }
 
+static bool trans_VCMLA_scalar(DisasContext *s, arg_VCMLA_scalar *a)
+{
+    gen_helper_gvec_3_ptr *fn_gvec_ptr;
+    int opr_sz;
+    TCGv_ptr fpst;
+    TCGContext *tcg_ctx = s->uc->tcg_ctx;
+
+    if (!dc_isar_feature(aa32_vcma, s)) {
+        return false;
+    }
+    if (a->size == 0 && !dc_isar_feature(aa32_fp16_arith, s)) {
+        return false;
+    }
+
+    /* UNDEF accesses to D16-D31 if they don't exist. */
+    if (!dc_isar_feature(aa32_simd_r32, s) &&
+        ((a->vd | a->vn | a->vm) & 0x10)) {
+        return false;
+    }
+
+    if ((a->vd | a->vn) & a->q) {
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    fn_gvec_ptr = (a->size ? gen_helper_gvec_fcmlas_idx
+                   : gen_helper_gvec_fcmlah_idx);
+    opr_sz = (1 + a->q) * 8;
+    fpst = get_fpstatus_ptr(s, 1);
+    tcg_gen_gvec_3_ptr(tcg_ctx, vfp_reg_offset(1, a->vd),
+                       vfp_reg_offset(1, a->vn),
+                       vfp_reg_offset(1, a->vm),
+                       fpst, opr_sz, opr_sz,
+                       (a->index << 2) | a->rot, fn_gvec_ptr);
+    tcg_temp_free_ptr(tcg_ctx, fpst);
+    return true;
+}

qemu/target/arm/translate.c

@@ -7182,31 +7182,7 @@ static int disas_neon_insn_2reg_scalar_ext(DisasContext *s, uint32_t insn)
     bool is_long = false, q = extract32(insn, 6, 1);
     bool ptr_is_env = false;
 
-    if ((insn & 0xff000f10) == 0xfe000800) {
+    if ((insn & 0xffb00f00) == 0xfe200d00) {
-        /* VCMLA (indexed) -- 1111 1110 S.RR .... .... 1000 ...0 .... */
-        int rot = extract32(insn, 20, 2);
-        int size = extract32(insn, 23, 1);
-        int index;
-
-        if (!dc_isar_feature(aa32_vcma, s)) {
-            return 1;
-        }
-        if (size == 0) {
-            if (!dc_isar_feature(aa32_fp16_arith, s)) {
-                return 1;
-            }
-            /* For fp16, rm is just Vm, and index is M.  */
-            rm = extract32(insn, 0, 4);
-            index = extract32(insn, 5, 1);
-        } else {
-            /* For fp32, rm is the usual M:Vm, and index is 0.  */
-            VFP_DREG_M(rm, insn);
-            index = 0;
-        }
-        data = (index << 2) | rot;
-        fn_gvec_ptr = (size ? gen_helper_gvec_fcmlas_idx
-                       : gen_helper_gvec_fcmlah_idx);
-    } else if ((insn & 0xffb00f00) == 0xfe200d00) {
         /* V[US]DOT -- 1111 1110 0.10 .... .... 1101 .Q.U .... */
         int u = extract32(insn, 4, 1);