target/arm: Move the vfp decodetree calls next to the base isa

Have the calls adjacent as an intermediate step toward
actually merging the decodes.

Backports commit f0f6d5c81be47d593e5ece7f06df6fba4c15738b from qemu

qemu/target/arm/translate.c

@@ -2728,32 +2728,6 @@ static void gen_neon_dup_high16(DisasContext *s, TCGv_i32 var)
     tcg_temp_free_i32(tcg_ctx, tmp);
 }
 
-/*
- * Disassemble a VFP instruction.  Returns nonzero if an error occurred
- * (ie. an undefined instruction).
- */
-static int disas_vfp_insn(DisasContext *s, uint32_t insn)
-{
-    /*
-     * If the decodetree decoder handles this insn it will always
-     * emit code to either execute the insn or generate an appropriate
-     * exception; so we don't need to ever return non-zero to tell
-     * the calling code to emit an UNDEF exception.
-     */
-    if (extract32(insn, 28, 4) == 0xf) {
-        if (disas_vfp_uncond(s, insn)) {
-            return 0;
-        }
-    } else {
-        if (disas_vfp(s, insn)) {
-            return 0;
-        }
-    }
-
-    /* If the decodetree decoder didn't handle this insn, it must be UNDEF */
-    return 1;
-}
-
 static inline bool use_goto_tb(DisasContext *s, target_ulong dest)
 {
 #ifndef CONFIG_USER_ONLY
@@ -11086,7 +11060,9 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
         ARCH(5);
 
         /* Unconditional instructions.  */
-        if (disas_a32_uncond(s, insn)) {
+        /* TODO: Perhaps merge these into one decodetree output file.  */
+        if (disas_a32_uncond(s, insn) ||
+            disas_vfp_uncond(s, insn)) {
             return;
         }
         /* fall back to legacy decoder */
@@ -11113,13 +11089,6 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
             }
             return;
         }
-        if ((insn & 0x0f000e10) == 0x0e000a00) {
-            /* VFP.  */
-            if (disas_vfp_insn(s, insn)) {
-                goto illegal_op;
-            }
-            return;
-        }
         if ((insn & 0x0e000f00) == 0x0c000100) {
             if (arm_dc_feature(s, ARM_FEATURE_IWMMXT)) {
                 /* iWMMXt register transfer.  */
@@ -11150,7 +11119,9 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
         arm_skip_unless(s, cond);
     }
 
-    if (disas_a32(s, insn)) {
+    /* TODO: Perhaps merge these into one decodetree output file.  */
+    if (disas_a32(s, insn) ||
+        disas_vfp(s, insn)) {
         return;
     }
     /* fall back to legacy decoder */
@@ -11160,11 +11131,10 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn)
     case 0xd:
     case 0xe:
         if (((insn >> 8) & 0xe) == 10) {
-            /* VFP.  */
+            /* VFP, but failed disas_vfp.  */
-            if (disas_vfp_insn(s, insn)) {
+            goto illegal_op;
-                goto illegal_op;
+        }
-            }
+        if (disas_coproc_insn(s, insn)) {
-        } else if (disas_coproc_insn(s, insn)) {
             /* Coprocessor.  */
             goto illegal_op;
         }
@@ -11253,7 +11223,14 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
         ARCH(6T2);
     }
 
-    if (disas_t32(s, insn)) {
+    /*
+     * TODO: Perhaps merge these into one decodetree output file.
+     * Note disas_vfp is written for a32 with cond field in the
+     * top nibble.  The t32 encoding requires 0xe in the top nibble.
+     */
+    if (disas_t32(s, insn) ||
+        disas_vfp_uncond(s, insn) ||
+        ((insn >> 28) == 0xe && disas_vfp(s, insn))) {
         return;
     }
     /* fall back to legacy decoder */
@@ -11270,17 +11247,15 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
                 goto illegal_op; /* op0 = 0b11 : unallocated */
             }
 
-            if (disas_vfp_insn(s, insn)) {
+            if (((insn >> 8) & 0xe) == 10 &&
-                if (((insn >> 8) & 0xe) == 10 &&
+                dc_isar_feature(aa32_fpsp_v2, s)) {
-                    dc_isar_feature(aa32_fpsp_v2, s)) {
+                /* FP, and the CPU supports it */
-                    /* FP, and the CPU supports it */
+                goto illegal_op;
-                    goto illegal_op;
+            } else {
-                } else {
+                /* All other insns: NOCP */
-                    /* All other insns: NOCP */
+                gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
-                    gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
+                                   syn_uncategorized(),
-                                       syn_uncategorized(),
+                                   default_exception_el(s));
-                                       default_exception_el(s));
-                }
             }
             break;
         }
@@ -11303,9 +11278,8 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
                 goto illegal_op;
             }
         } else if (((insn >> 8) & 0xe) == 10) {
-            if (disas_vfp_insn(s, insn)) {
+            /* VFP, but failed disas_vfp.  */
-                goto illegal_op;
+            goto illegal_op;
-            }
         } else {
             if (insn & (1 << 28))
                 goto illegal_op;