target/arm: Convert Neon VDUP (scalar) to decodetree

Convert the Neon VDUP (scalar) insn to decodetree.  (Note that we
can't call this just "VDUP" as we used that already in vfp.decode for
the "VDUP (general purpose register" insn.)

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

3 files changed, 34 insertions, 24 deletions

diff --git a/target/arm/neon-dp.decode b/target/arm/neon-dp.decode
index 91bc770dfb..6d890b2161 100644
--- a/target/arm/neon-dp.decode
+++ b/target/arm/neon-dp.decode
@@ -422,6 +422,13 @@ Vimm_1r          1111 001 . 1 . 000 ... .... cmode:4 0 . op:1 1 .... @1reg_imm
 
     VTBL         1111 001 1 1 . 11 .... .... 10 len:2 . op:1 . 0 .... \
                  vm=%vm_dp vn=%vn_dp vd=%vd_dp
+
+    VDUP_scalar  1111 001 1 1 . 11 index:3 1 .... 11 000 q:1 . 0 .... \
+                 vm=%vm_dp vd=%vd_dp size=0
+    VDUP_scalar  1111 001 1 1 . 11 index:2 10 .... 11 000 q:1 . 0 .... \
+                 vm=%vm_dp vd=%vd_dp size=1
+    VDUP_scalar  1111 001 1 1 . 11 index:1 100 .... 11 000 q:1 . 0 .... \
+                 vm=%vm_dp vd=%vd_dp size=2
   ]
 
   # Subgroup for size != 0b11
diff --git a/target/arm/translate-neon.inc.c b/target/arm/translate-neon.inc.c
index da0e5dbc6f..a5aa56bbde 100644
--- a/target/arm/translate-neon.inc.c
+++ b/target/arm/translate-neon.inc.c
@@ -2944,3 +2944,29 @@ static bool trans_VTBL(DisasContext *s, arg_VTBL *a)
     tcg_temp_free_i32(tmp);
     return true;
 }
+
+static bool trans_VDUP_scalar(DisasContext *s, arg_VDUP_scalar *a)
+{
+    if (!arm_dc_feature(s, ARM_FEATURE_NEON)) {
+        return false;
+    }
+
+    /* UNDEF accesses to D16-D31 if they don't exist. */
+    if (!dc_isar_feature(aa32_simd_r32, s) &&
+        ((a->vd | a->vm) & 0x10)) {
+        return false;
+    }
+
+    if (a->vd & a->q) {
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    tcg_gen_gvec_dup_mem(a->size, neon_reg_offset(a->vd, 0),
+                         neon_element_offset(a->vm, a->index, a->size),
+                         a->q ? 16 : 8, a->q ? 16 : 8);
+    return true;
+}
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 0c6425928f..6d18892ade 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -5574,31 +5574,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                     }
                     break;
                 }
-            } else if ((insn & (1 << 10)) == 0) {
-                /* VTBL, VTBX: handled by decodetree */
-                return 1;
-            } else if ((insn & 0x380) == 0) {
-                /* VDUP */
-                int element;
-                MemOp size;
-
-                if ((insn & (7 << 16)) == 0 || (q && (rd & 1))) {
-                    return 1;
-                }
-                if (insn & (1 << 16)) {
-                    size = MO_8;
-                    element = (insn >> 17) & 7;
-                } else if (insn & (1 << 17)) {
-                    size = MO_16;
-                    element = (insn >> 18) & 3;
-                } else {
-                    size = MO_32;
-                    element = (insn >> 19) & 1;
-                }
-                tcg_gen_gvec_dup_mem(size, neon_reg_offset(rd, 0),
-                                     neon_element_offset(rm, element, size),
-                                     q ? 16 : 8, q ? 16 : 8);
             } else {
+                /* VTBL, VTBX, VDUP: handled by decodetree */
                 return 1;
             }
         }