68000 address error predecrement addressing mode special case fixes, ADD.X/SUB.X...

diff --git a/gencpu.cpp b/gencpu.cpp
index b89f6a9f4aa33078751143d43e3e0147150c270f..830f163eb7377753e77d37448e66e44137b4831f 100644 (file)
--- a/gencpu.cpp
+++ b/gencpu.cpp
@@ -87,6 +87,7 @@ static int disp020cnt;
 static bool candormw;
 static bool genastore_done;
 static char rmw_varname[100];
+static struct instr *g_instr;
 
 #define GENA_GETV_NO_FETCH     0
 #define GENA_GETV_FETCH                1
@@ -1474,6 +1475,8 @@ static void genamode2x (amodes mode, const char *reg, wordsizes size, const char
                        insn_n_cycles += 2;
                        count_cycles_ea += 2;
                        pc_68000_offset_fetch += 2;
+                       if (size == sz_long)
+                               pc_68000_offset_fetch -= 2;
                }
                break;
        case Ad16: // (d16,An)
@@ -1647,13 +1650,27 @@ static void genamode2x (amodes mode, const char *reg, wordsizes size, const char
                exception_pc_offset = pc_68000_offset + pc_68000_offset_fetch;
        }
 
+       // check possible address error (if 68000/010 and enabled)
        if ((using_prefetch || using_ce) && using_exception_3 && getv != 0 && size != sz_byte) {
                printf ("\tif (%sa & 1) {\n", name);
+
+               if (g_instr->mnemo == i_ADDX || g_instr->mnemo == i_SUBX) {
+                       // ADDX/SUBX special case
+                       if (g_instr->size == sz_word) {
+                               printf("\t\tm68k_areg (regs, %s) = %sa;\n", reg, name);
+                       }
+               } else if (mode == Apdi) {
+                       // 68000 decrements register first, then checks for address error
+                       printf("\t\tm68k_areg (regs, %s) = %sa;\n", reg, name);
+               }
+
                if (exception_pc_offset)
                        incpc("%d", exception_pc_offset);
+
                // MOVE.L EA,-(An) causing address error: stacked value is original An - 2, not An - 4.
                if ((flags & (GF_REVERSE | GF_REVERSE2)) && size == sz_long && mode == Apdi)
                        printf("\t\t%sa += %d;\n", name, flags & GF_REVERSE2 ? -2 : 2);
+
                printf ("\t\texception3_%s(opcode, %sa);\n", getv == 2 ? "write" : "read", name);
                printf ("\t\tgoto %s;\n", endlabelstr);
                printf ("\t}\n");
@@ -3196,6 +3213,7 @@ static void gen_opcode (unsigned int opcode)
        start_brace ();
 
        m68k_pc_offset = 2;
+       g_instr = curi;
 
        // do not unnecessarily create useless mmuop030
        // functions when CPU is not 68030