sms: add pause support

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

diff --git a/cpu/DrZ80/drz80.s b/cpu/DrZ80/drz80.s
index edb29df..ff2a6b8 100644 (file)
--- a/cpu/DrZ80/drz80.s
+++ b/cpu/DrZ80/drz80.s
@@ -97,6 +97,7 @@ DrZ80Ver: .long 0x0001
        .equ Z80_IF1, 1<<0\r
        .equ Z80_IF2, 1<<1\r
        .equ Z80_HALT, 1<<2\r
+       .equ Z80_NMI, 1<<3\r
 \r
 ;@---------------------------------------\r
 \r
@@ -1359,9 +1360,11 @@ DrZ80Run:
 \r
 .if INTERRUPT_MODE == 0\r
        ;@ check ints\r
+       tst r0,#(Z80_NMI<<8)\r
+       blne DoNMI\r
        tst r0,#0xff\r
        movne r0,r0,lsr #8\r
-       tstne r0,#1\r
+       tstne r0,#Z80_IF1\r
        blne DoInterrupt\r
 .endif\r
 \r
@@ -1515,6 +1518,36 @@ DoInterrupt_end:
        ldmfd sp!,{pc} ;@ return\r
 .endif\r
 \r
+DoNMI:\r
+       stmfd sp!,{lr}\r
+\r
+       bic r0,r0,#((Z80_NMI|Z80_HALT|Z80_IF1)<<8)\r
+       strh r0,[cpucontext,#z80irq] @ 0x4C, irq and IFF bits\r
+\r
+       ;@ push pc on stack\r
+       ldr r0,[cpucontext,#z80pc_base]\r
+       sub r2,z80pc,r0\r
+       opPUSHareg r2\r
+\r
+       ;@ read new pc from vector address\r
+.if UPDATE_CONTEXT\r
+       str z80pc,[cpucontext,#z80pc_pointer]\r
+.endif\r
+       mov r0,#0x66\r
+.if DRZ80_XMAP\r
+       rebasepc\r
+.else\r
+       stmfd sp!,{r3,r12}\r
+       mov lr,pc\r
+       ldr pc,[cpucontext,#z80_rebasePC] ;@ r0=new pc - external function sets z80pc_base and returns new z80pc in r0\r
+       ldmfd sp!,{r3,r12}\r
+       mov z80pc,r0    \r
+.endif\r
+       ldrh r0,[cpucontext,#z80irq] @ 0x4C, irq and IFF bits\r
+       eatcycles 11\r
+       ldmfd sp!,{pc}\r
+\r
+\r
 .data\r
 .align 4\r
 \r
@@ -5615,7 +5648,7 @@ ei_return:
        ;@ check ints\r
        tst r0,#0xff\r
        movne r0,r0,lsr #8\r
-       tstne r0,#1\r
+       tstne r0,#Z80_IF1\r
        blne DoInterrupt\r
 \r
        ;@ continue\r