adjusted timing and fixed EI in DrZ80

git-svn-id: file:///home/notaz/opt/svn/PicoDrive@472 be3aeb3a-fb24-0410-a615-afba39da0efa

diff --git a/cpu/DrZ80/drz80.s b/cpu/DrZ80/drz80.s
index 1061910..846c636 100644 (file)
--- a/cpu/DrZ80/drz80.s
+++ b/cpu/DrZ80/drz80.s
@@ -360,8 +360,8 @@ pico_z80_write16: @ data, addr
      str z80pc,[cpucontext,#z80pc_pointer]\r
 .endif\r
 .if DRZ80_FOR_PICODRIVE\r
-    bic r0,r0,#0xfe000\r
     ldr r1,[cpucontext,#z80pc_base]\r
+    bic r0,r0,#0xfe000\r
     add z80pc,r1,r0\r
 .else\r
     stmfd sp!,{r3,r12}\r
@@ -1372,30 +1372,32 @@ DrZ80Run:
        mov z80_icount,r1                                               ;@ setup number of Tstates to execute\r
 \r
 .if INTERRUPT_MODE == 0\r
-       ldrh r0,[cpucontext,#z80irq] @ 0x4C\r
+       ldrh r0,[cpucontext,#z80irq] @ 0x4C, irq and IFF bits\r
 .endif\r
        ldmia cpucontext,{z80pc-z80sp}                  ;@ load Z80 registers\r
 \r
 .if INTERRUPT_MODE == 0\r
        ;@ check ints\r
-       tst r0,#1\r
-       movnes r0,r0,lsr #8\r
-    blne DoInterrupt\r
+       tst r0,#0xff\r
+       movne r0,r0,lsr #8\r
+       tstne r0,#1\r
+       blne DoInterrupt\r
 .endif\r
 \r
-       ldrb r0,[z80pc],#1    ;@ get first op code\r
        ldr opcodes,MAIN_opcodes_POINTER2\r
-       ldr pc,[opcodes,r0, lsl #2]  ;@ execute op code\r
 \r
-MAIN_opcodes_POINTER2: .word MAIN_opcodes\r
+       cmp z80_icount,#0     ;@ irq might have used all cycles\r
+       ldrplb r0,[z80pc],#1\r
+       ldrpl pc,[opcodes,r0, lsl #2]\r
 \r
 \r
 z80_execute_end:\r
        ;@ save registers in CPU context\r
        stmia cpucontext,{z80pc-z80sp}                  ;@ save Z80 registers\r
-    mov r0,z80_icount\r
+       mov r0,z80_icount\r
        ldmia sp!,{r4-r12,pc}                                   ;@ restore registers from stack and return to C code\r
 \r
+MAIN_opcodes_POINTER2: .word MAIN_opcodes\r
 .if INTERRUPT_MODE\r
 Interrupt_local: .word Interrupt\r
 .endif\r
@@ -1414,6 +1416,8 @@ DoInterrupt:
        ldmia cpucontext,{z80pc-z80sp}                  ;@ load Z80 registers\r
        mov pc,lr ;@ return\r
 .else\r
+\r
+       ;@ r0 == z80if\r
        stmfd sp!,{lr}\r
 \r
        tst r0,#4 ;@ check halt\r
@@ -1426,10 +1430,9 @@ DoInterrupt:
        strb r0,[cpucontext,#z80if]\r
 \r
        ;@ now check int mode\r
-    tst r1,#1\r
-    bne DoInterrupt_mode1\r
-    tst r1,#2\r
-    bne DoInterrupt_mode2\r
+       cmp r1,#1\r
+       beq DoInterrupt_mode1\r
+       bgt DoInterrupt_mode2\r
 \r
 DoInterrupt_mode0:\r
        ;@ get 3 byte vector\r
@@ -1459,6 +1462,7 @@ DoInterrupt_mode0:
        ;@ rebase new pc\r
        rebasepc\r
 \r
+       eatcycles 13\r
        b DoInterrupt_end\r
 \r
 1:\r
@@ -1473,6 +1477,7 @@ DoInterrupt_mode0:
        ;@ rebase new pc\r
        rebasepc\r
 \r
+       eatcycles 13\r
        b DoInterrupt_end\r
 \r
 DoInterrupt_mode1:\r
@@ -1482,6 +1487,7 @@ DoInterrupt_mode1:
        mov r0,#0x38\r
        rebasepc\r
 \r
+       eatcycles 13\r
        b DoInterrupt_end\r
 \r
 DoInterrupt_mode2:\r
@@ -1518,18 +1524,19 @@ DoInterrupt_mode2:
        ldmfd sp!,{r3,r12}\r
        mov z80pc,r0    \r
 .endif\r
+       eatcycles 17\r
 \r
 DoInterrupt_end:\r
        ;@ interupt accepted so callback irq interface\r
        ldr r0,[cpucontext, #z80irqcallback]\r
        tst r0,r0\r
+       streqb r0,[cpucontext,#z80irq]       ;@ default handling\r
        ldmeqfd sp!,{pc}\r
        stmfd sp!,{r3,r12}\r
        mov lr,pc\r
        mov pc,r0    ;@ call callback function\r
        ldmfd sp!,{r3,r12}\r
        ldmfd sp!,{pc} ;@ return\r
-\r
 .endif\r
 \r
 .data\r
@@ -5194,7 +5201,7 @@ opcode_C_8:
        fetch 5\r
 \r
 opcode_C_9_cond:\r
-       sub z80_icount,#1\r
+       eatcycles 1\r
 ;@RET\r
 opcode_C_9:\r
     opPOP\r
@@ -5615,13 +5622,12 @@ EI_DUMMY_opcodes_POINTER: .word EI_DUMMY_opcodes
 ;@EI\r
 opcode_F_B:\r
        ldrb r1,[cpucontext,#z80if]\r
-       tst r1,#Z80_IF1\r
-       bne ei_return_exit\r
-\r
+       mov r2,opcodes\r
        orr r1,r1,#(Z80_IF1)|(Z80_IF2)\r
        strb r1,[cpucontext,#z80if]\r
 \r
-       mov r2,opcodes\r
+       ldrb r0,[z80pc],#1\r
+       eatcycles 4\r
        ldr opcodes,EI_DUMMY_opcodes_POINTER\r
        ldr pc,[r2,r0, lsl #2]\r
 \r
@@ -5629,16 +5635,17 @@ ei_return:
        ;@point that program returns from EI to check interupts\r
        ;@an interupt can not be taken directly after a EI opcode\r
        ;@ reset z80pc and opcode pointer\r
-       ldrh r0,[cpucontext,#z80irq] @ 0x4C\r
+       ldrh r0,[cpucontext,#z80irq] @ 0x4C, irq and IFF bits\r
        sub z80pc,z80pc,#1\r
        ldr opcodes,MAIN_opcodes_POINTER\r
        ;@ check ints\r
-       tst r0,#1\r
-       movnes r0,r0,lsr #8\r
-    blne DoInterrupt\r
+       tst r0,#0xff\r
+       movne r0,r0,lsr #8\r
+       tstne r0,#1\r
+       blne DoInterrupt\r
+\r
        ;@ continue\r
-ei_return_exit:\r
-       fetch 4\r
+       fetch 0\r
 \r
 ;@CALL M,NN\r
 opcode_F_C:\r
@@ -8048,5 +8055,5 @@ opcode_ED_BB:
 ;@end_loop:\r
 ;@     b end_loop\r
 \r
-\r
+;@ vim:filetype=armasm\r
 \r