drZ80 separation finished, related bugs fixed

[picodrive.git] / cpu / DrZ80 / drz80.s

diff --git a/cpu/DrZ80/drz80.s b/cpu/DrZ80/drz80.s
index 5445ffd..a623451 100644 (file)
--- a/cpu/DrZ80/drz80.s
+++ b/cpu/DrZ80/drz80.s
@@ -14,12 +14,12 @@
       .equiv INTERRUPT_MODE,         0 ;@0 = Use internal int handler, 1 = Use Mames int handler\r
       .equiv FAST_Z80SP,             1 ;@0 = Use mem functions for stack pointer, 1 = Use direct mem pointer\r
       .equiv UPDATE_CONTEXT,         0\r
-      .equiv DRZ80_FOR_PICODRIVE,    1\r
       .equiv DRZ80_XMAP,             1\r
       .equiv DRZ80_XMAP_MORE_INLINE, 1\r
 \r
 .if DRZ80_XMAP\r
       .equ Z80_MEM_SHIFT, 13\r
+      ;@ note: stack is locked in single bank that z80sp_base points to\r
 .endif\r
 \r
 .if INTERRUPT_MODE\r
@@ -160,14 +160,14 @@ z80_xmap_read16: @ addr
 \r
 0:\r
     @ z80_xmap_read8 will save r3 and r12 for us\r
-    stmfd sp!,{r4,r5,lr}\r
-    mov r4,r0\r
+    stmfd sp!,{r8,r9,lr}\r
+    mov r8,r0\r
     bl z80_xmap_read8\r
-    mov r5,r0\r
-    add r0,r4,#1\r
+    mov r9,r0\r
+    add r0,r8,#1\r
     bl z80_xmap_read8\r
-    orr r0,r5,r0,lsl #8\r
-    ldmfd sp!,{r4,r5,pc}\r
+    orr r0,r9,r0,lsl #8\r
+    ldmfd sp!,{r8,r9,pc}\r
 \r
 z80_xmap_write16: @ data, addr\r
     add r2,r1,#1\r
@@ -187,14 +187,30 @@ z80_xmap_write16: @ data, addr
     bx lr\r
 \r
 0:\r
-    stmfd sp!,{r4,r5,lr}\r
-    mov r4,r0\r
-    mov r5,r1\r
+    stmfd sp!,{r8,r9,lr}\r
+    mov r8,r0\r
+    mov r9,r1\r
     bl z80_xmap_write8\r
-    mov r0,r4,lsr #8\r
-    add r1,r5,#1\r
+    mov r0,r8,lsr #8\r
+    add r1,r9,#1\r
     bl z80_xmap_write8\r
-    ldmfd sp!,{r4,r5,pc}\r
+    ldmfd sp!,{r8,r9,pc}\r
+\r
+z80_xmap_rebase_pc:\r
+    ldr r1,[cpucontext,#z80_read8]\r
+    mov r2,r0,lsr #Z80_MEM_SHIFT\r
+    ldr r1,[r1,r2,lsl #2]\r
+    movs r1,r1,lsl #1\r
+    strcc r1,[cpucontext,#z80pc_base]\r
+    addcc z80pc,r1,r0\r
+    bxcc lr\r
+\r
+z80_bad_jump:\r
+    ldr r0,[cpucontext,#z80_read8]\r
+    ldr r0,[r0]\r
+    str r0,[cpucontext,#z80pc_base]\r
+    mov z80pc,r0\r
+    bx lr\r
 .endif\r
 \r
 \r
@@ -335,10 +351,8 @@ z80_xmap_write16: @ data, addr
 .if UPDATE_CONTEXT\r
      str z80pc,[cpucontext,#z80pc_pointer]\r
 .endif\r
-.if DRZ80_FOR_PICODRIVE\r
-    ldr r1,[cpucontext,#z80pc_base]\r
-    bic r0,r0,#0xfe000\r
-    add z80pc,r1,r0\r
+.if DRZ80_XMAP\r
+    bl z80_xmap_rebase_pc\r
 .else\r
     stmfd sp!,{r3,r12}\r
        mov lr,pc\r
@@ -352,9 +366,10 @@ z80_xmap_write16: @ data, addr
 .if UPDATE_CONTEXT\r
      str z80pc,[cpucontext,#z80pc_pointer]\r
 .endif\r
-.if DRZ80_FOR_PICODRIVE\r
-    bic r0,r0,#0xfe000\r
+.if DRZ80_XMAP\r
+    ;@ XXX: SP is locked to single back z80sp_base points to.\r
     ldr r1,[cpucontext,#z80sp_base]\r
+    bic r0,r0,#0x7f<<Z80_MEM_SHIFT\r
     add r0,r1,r0\r
 .else\r
        stmfd sp!,{r3,r12}\r
@@ -722,22 +737,9 @@ z80_xmap_write16: @ data, addr
 \r
 .macro opPOP\r
 .if FAST_Z80SP\r
-.if DRZ80_FOR_PICODRIVE\r
-    @ notaz: try to protect against stack overflows, which tend to happen in Picodrive because of poor timing\r
-    ldr r2,[cpucontext,#z80sp_base]\r
-       ldrb r0,[z80sp],#1\r
-    add r2,r2,#0x2000\r
-    cmp z80sp,r2\r
-@    subge z80sp,z80sp,#0x2000 @ unstable?\r
-       ldrb r1,[z80sp],#1\r
-    cmp z80sp,r2\r
-@    subge z80sp,z80sp,#0x2000\r
-       orr r0,r0,r1, lsl #8\r
-.else\r
        ldrb r0,[z80sp],#1\r
        ldrb r1,[z80sp],#1\r
        orr r0,r0,r1, lsl #8\r
-.endif\r
 .else\r
        mov r0,z80sp\r
        readmem16\r
@@ -752,23 +754,22 @@ z80_xmap_write16: @ data, addr
 .endm\r
 ;@---------------------------------------\r
 \r
+.macro stack_check\r
+    @ try to protect against stack overflows, lock into current bank\r
+    ldr r1,[cpucontext,#z80sp_base]\r
+    sub r1,z80sp,r1\r
+    cmp r1,#2\r
+    addlt z80sp,z80sp,#1<<Z80_MEM_SHIFT\r
+.endm\r
+\r
 .macro opPUSHareg reg @ reg > r1\r
 .if FAST_Z80SP\r
-.if DRZ80_FOR_PICODRIVE\r
-    @ notaz: try to protect against stack overflows, which tend to happen in Picodrive because of poor timing\r
-    ldr r0,[cpucontext,#z80sp_base]\r
-    cmp z80sp,r0\r
-    addle z80sp,z80sp,#0x2000\r
-    mov r1,\reg, lsr #8\r
-       strb r1,[z80sp,#-1]!\r
-    cmp z80sp,r0\r
-    addle z80sp,z80sp,#0x2000\r
-       strb \reg,[z80sp,#-1]!\r
-.else\r
+.if DRZ80_XMAP\r
+       stack_check\r
+.endif\r
        mov r1,\reg, lsr #8\r
        strb r1,[z80sp,#-1]!\r
        strb \reg,[z80sp,#-1]!\r
-.endif\r
 .else\r
     mov r0,\reg\r
        sub z80sp,z80sp,#2\r
@@ -779,22 +780,13 @@ z80_xmap_write16: @ data, addr
 \r
 .macro opPUSHreg reg\r
 .if FAST_Z80SP\r
-.if DRZ80_FOR_PICODRIVE\r
-    ldr r0,[cpucontext,#z80sp_base]\r
-    cmp z80sp,r0\r
-    addle z80sp,z80sp,#0x2000\r
-    mov r1,\reg, lsr #24\r
-       strb r1,[z80sp,#-1]!\r
-    cmp z80sp,r0\r
-    addle z80sp,z80sp,#0x2000\r
-       mov r1,\reg, lsr #16\r
-       strb r1,[z80sp,#-1]!\r
-.else\r
+.if DRZ80_XMAP\r
+       stack_check\r
+.endif\r
     mov r1,\reg, lsr #24\r
        strb r1,[z80sp,#-1]!\r
        mov r1,\reg, lsr #16\r
        strb r1,[z80sp,#-1]!\r
-.endif\r
 .else\r
        mov r0,\reg,lsr #16\r
        sub z80sp,z80sp,#2\r