target-arm/translate-a64.c: Unify some of the ldst_reg decoding

The various load/store variants under disas_ldst_reg can all reuse the
same decoding for opc, size, rt and is_vector.

This patch unifies the decoding in preparation for generating
instruction syndromes for data aborts.
This will allow us to reduce the number of places to hook in updates
to the load/store state needed to generate the insn syndromes.

No functional change.

Backports commit cd694521ca061a5d0436d5df4ec8c17c8f4dfcdb from qemu

qemu/target-arm/translate-a64.c

@@ -2130,20 +2130,20 @@ static void disas_ldst_pair(DisasContext *s, uint32_t insn)
  * size: 00 -> 8 bit, 01 -> 16 bit, 10 -> 32 bit, 11 -> 64bit
  * opc: 00 -> store, 01 -> loadu, 10 -> loads 64, 11 -> loads 32
  */
-static void disas_ldst_reg_imm9(DisasContext *s, uint32_t insn)
+static void disas_ldst_reg_imm9(DisasContext *s, uint32_t insn,
+                                int opc,
+                                int size,
+                                int rt,
+                                bool is_vector)
 {
     TCGContext *tcg_ctx = s->uc->tcg_ctx;
-    int rt = extract32(insn, 0, 5);
     int rn = extract32(insn, 5, 5);
     int imm9 = sextract32(insn, 12, 9);
-    int opc = extract32(insn, 22, 2);
-    int size = extract32(insn, 30, 2);
     int idx = extract32(insn, 10, 2);
     bool is_signed = false;
     bool is_store = false;
     bool is_extended = false;
     bool is_unpriv = (idx == 2);
-    bool is_vector = extract32(insn, 26, 1);
     bool post_index;
     bool writeback;
 
@@ -2250,20 +2250,20 @@ static void disas_ldst_reg_imm9(DisasContext *s, uint32_t insn)
  * Rn: address register or SP for base
  * Rm: offset register or ZR for offset
  */
-static void disas_ldst_reg_roffset(DisasContext *s, uint32_t insn)
+static void disas_ldst_reg_roffset(DisasContext *s, uint32_t insn,
+                                   int opc,
+                                   int size,
+                                   int rt,
+                                   bool is_vector)
 {
     TCGContext *tcg_ctx = s->uc->tcg_ctx;
-    int rt = extract32(insn, 0, 5);
     int rn = extract32(insn, 5, 5);
     int shift = extract32(insn, 12, 1);
     int rm = extract32(insn, 16, 5);
-    int opc = extract32(insn, 22, 2);
     int opt = extract32(insn, 13, 3);
-    int size = extract32(insn, 30, 2);
     bool is_signed = false;
     bool is_store = false;
     bool is_extended = false;
-    bool is_vector = extract32(insn, 26, 1);
 
     TCGv_i64 tcg_rm;
     TCGv_i64 tcg_addr;
@@ -2340,15 +2340,15 @@ static void disas_ldst_reg_roffset(DisasContext *s, uint32_t insn)
  * Rn: base address register (inc SP)
  * Rt: target register
  */
-static void disas_ldst_reg_unsigned_imm(DisasContext *s, uint32_t insn)
+static void disas_ldst_reg_unsigned_imm(DisasContext *s, uint32_t insn,
+                                        int opc,
+                                        int size,
+                                        int rt,
+                                        bool is_vector)
 {
     TCGContext *tcg_ctx = s->uc->tcg_ctx;
-    int rt = extract32(insn, 0, 5);
     int rn = extract32(insn, 5, 5);
     unsigned int imm12 = extract32(insn, 10, 12);
-    bool is_vector = extract32(insn, 26, 1);
-    int size = extract32(insn, 30, 2);
-    int opc = extract32(insn, 22, 2);
     unsigned int offset;
 
     TCGv_i64 tcg_addr;
@@ -2407,20 +2407,25 @@ static void disas_ldst_reg_unsigned_imm(DisasContext *s, uint32_t insn)
 /* Load/store register (all forms) */
 static void disas_ldst_reg(DisasContext *s, uint32_t insn)
 {
+    int rt = extract32(insn, 0, 5);
+    int opc = extract32(insn, 22, 2);
+    bool is_vector = extract32(insn, 26, 1);
+    int size = extract32(insn, 30, 2);
+
     switch (extract32(insn, 24, 2)) {
     case 0:
         if (extract32(insn, 21, 1) == 1 && extract32(insn, 10, 2) == 2) {
-            disas_ldst_reg_roffset(s, insn);
+            disas_ldst_reg_roffset(s, insn, opc, size, rt, is_vector);
         } else {
             /* Load/store register (unscaled immediate)
              * Load/store immediate pre/post-indexed
              * Load/store register unprivileged
              */
-            disas_ldst_reg_imm9(s, insn);
+            disas_ldst_reg_imm9(s, insn, opc, size, rt, is_vector);
         }
         break;
     case 1:
-        disas_ldst_reg_unsigned_imm(s, insn);
+        disas_ldst_reg_unsigned_imm(s, insn, opc, size, rt, is_vector);
         break;
     default:
         unallocated_encoding(s);