target-arm: fix SRS/RFE instructions

The encoding of 'IA' and 'DB' conditions was swapped.
SRS instruction must store banked SPSR instead of CPSR at the specific address.
Missing 'return' statement at the end of RFE handling.
Fixed write-back code to reference correct registers.

From: Hyeonsung Jang <hsjang@ok-labs.com>
Signed-off-by: NFilip Navara <filip.navara@gmail.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

target-arm/translate.c

@@ -5749,7 +5749,7 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
             }
         } else if ((insn & 0x0e5fffe0) == 0x084d0500) {
             /* srs */
-            uint32_t offset;
+            int32_t offset;
             if (IS_USER(s))
                 goto illegal_op;
             ARCH(6);
@@ -5763,8 +5763,8 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
             i = (insn >> 23) & 3;
             switch (i) {
             case 0: offset = -4; break; /* DA */
-            case 1: offset = -8; break; /* DB */
-            case 2: offset = 0; break; /* IA */
+            case 1: offset = 0; break; /* IA */
+            case 2: offset = -8; break; /* DB */
             case 3: offset = 4; break; /* IB */
             default: abort();
             }
@@ -5772,32 +5772,32 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
                 tcg_gen_addi_i32(addr, addr, offset);
             tmp = load_reg(s, 14);
             gen_st32(tmp, addr, 0);
-            tmp = new_tmp();
-            gen_helper_cpsr_read(tmp);
+            tmp = load_cpu_field(spsr);
             tcg_gen_addi_i32(addr, addr, 4);
             gen_st32(tmp, addr, 0);
             if (insn & (1 << 21)) {
                 /* Base writeback.  */
                 switch (i) {
                 case 0: offset = -8; break;
-                case 1: offset = -4; break;
-                case 2: offset = 4; break;
+                case 1: offset = 4; break;
+                case 2: offset = -4; break;
                 case 3: offset = 0; break;
                 default: abort();
                 }
                 if (offset)
-                    tcg_gen_addi_i32(addr, tmp, offset);
+                    tcg_gen_addi_i32(addr, addr, offset);
                 if (op1 == (env->uncached_cpsr & CPSR_M)) {
-                    gen_movl_reg_T1(s, 13);
+                    store_reg(s, 13, addr);
                 } else {
-                    gen_helper_set_r13_banked(cpu_env, tcg_const_i32(op1), cpu_T[1]);
+                    gen_helper_set_r13_banked(cpu_env, tcg_const_i32(op1), addr);
+                    dead_tmp(addr);
                 }
             } else {
                 dead_tmp(addr);
             }
         } else if ((insn & 0x0e5fffe0) == 0x081d0a00) {
             /* rfe */
-            uint32_t offset;
+            int32_t offset;
             if (IS_USER(s))
                 goto illegal_op;
             ARCH(6);
@@ -5806,8 +5806,8 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
             i = (insn >> 23) & 3;
             switch (i) {
             case 0: offset = -4; break; /* DA */
-            case 1: offset = -8; break; /* DB */
-            case 2: offset = 0; break; /* IA */
+            case 1: offset = 0; break; /* IA */
+            case 2: offset = -8; break; /* DB */
             case 3: offset = 4; break; /* IB */
             default: abort();
             }
@@ -5821,8 +5821,8 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
                 /* Base writeback.  */
                 switch (i) {
                 case 0: offset = -8; break;
-                case 1: offset = -4; break;
-                case 2: offset = 4; break;
+                case 1: offset = 4; break;
+                case 2: offset = -4; break;
                 case 3: offset = 0; break;
                 default: abort();
                 }
@@ -5833,6 +5833,7 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
                 dead_tmp(addr);
             }
             gen_rfe(s, tmp, tmp2);
+            return;
         } else if ((insn & 0x0e000000) == 0x0a000000) {
             /* branch link and change to thumb (blx <offset>) */
             int32_t offset;