games/snes: cpu timing fix

5 files changed, 14 insertions, 12 deletions

diff --git a/sys/src/games/snes/cpu.c b/sys/src/games/snes/cpu.c
index c52683e80..602d4ca8f 100644
--- a/sys/src/games/snes/cpu.c
+++ b/sys/src/games/snes/cpu.c
@@ -609,11 +609,8 @@ enum { COP = 0, BRK = 1, NMI = 3, IRQ = 5 };
 static void
 interrupt(int src)
 {
-	if(src > BRK){
-		io();
-		if(!emu)
-			io();
-	}
+	if(src > BRK)
+		memread(pc | rPB);
 	if(!emu)
 		push8(rPB >> 16);
 	push16(pc);
@@ -687,7 +684,6 @@ cpustep(void)
 	lastpc = curpc;
 	if(trace)
 		print("%.6x %.2x A=%.4x X=%.4x Y=%.4x P=%.2x %.2x\n", curpc, op, rA, rX, rY, rP, rS);
-	cyc = 0;
 	switch(op){
 	case 0x00: fetch8(); interrupt(BRK); break;
 	case 0x01: nz(rA |= mem816(dpi(0, 1, 0), 0)); break;
diff --git a/sys/src/games/snes/dat.h b/sys/src/games/snes/dat.h
index 2a0b53223..86a14a5a4 100644
--- a/sys/src/games/snes/dat.h
+++ b/sys/src/games/snes/dat.h
@@ -24,7 +24,7 @@ extern u16int spc;
 extern u8int dspstate;
 extern u16int dspcounter, noise;
 
-extern int ppuclock, spcclock, dspclock, stimerclock;
+extern int ppuclock, spcclock, dspclock, stimerclock, cpupause;
 extern int battery, saveclock, scale, mouse;
 
 enum {
diff --git a/sys/src/games/snes/mem.c b/sys/src/games/snes/mem.c
index 1bd839dc2..6fea74bfd 100644
--- a/sys/src/games/snes/mem.c
+++ b/sys/src/games/snes/mem.c
@@ -183,7 +183,7 @@ regread(u16int p)
 			reg[OPCTLATCH] &= ~3;
 		return mdr2 = reg[p] | v | mdr2 & 0x20;
 	case 0x2180:
-		v = memread(0x7e0000 | reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16);
+		v = mem[reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16];
 		incwram();
 		return v;
 	case 0x4016:
@@ -337,7 +337,7 @@ regwrite(u16int p, u8int v)
 	case 0x213e:
 		return;
 	case 0x2180:
-		memwrite(0x7e0000 | reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16, v);
+		mem[reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16] = v;
 		incwram();
 		return;
 	case 0x4016:
diff --git a/sys/src/games/snes/ppu.c b/sys/src/games/snes/ppu.c
index 7e9228fe9..1f2175a49 100644
--- a/sys/src/games/snes/ppu.c
+++ b/sys/src/games/snes/ppu.c
@@ -857,9 +857,11 @@ ppustep(void)
 			pixeldraw(rx, ppuy - 1, ppuy >= yvbl ? 0x31c8 : 0);
 	}
 
+	if(ppux == 134)
+		cpupause = 1;
 	if(ppux == 0x116 && ppuy <= yvbl)
 		hdma |= reg[0x420c];
-	if((reg[NMITIMEN] & HCNTIRQ) != 0 && htime == ppux && ((reg[NMITIMEN] & VCNTIRQ) == 0 || vtime == ppuy))
+	if((reg[NMITIMEN] & HCNTIRQ) != 0 && htime+4 == ppux && ((reg[NMITIMEN] & VCNTIRQ) == 0 || vtime == ppuy))
 		irq |= IRQPPU;
 	if(++ppux >= 340){
 		ppux = 0;
diff --git a/sys/src/games/snes/snes.c b/sys/src/games/snes/snes.c
index f6bd85567..0d7800b30 100644
--- a/sys/src/games/snes/snes.c
+++ b/sys/src/games/snes/snes.c
@@ -11,7 +11,7 @@
 uchar *prg, *sram;
 int nprg, nsram, hirom, battery;
 
-int ppuclock, spcclock, dspclock, stimerclock, saveclock, msgclock, paused, perfclock;
+int ppuclock, spcclock, dspclock, stimerclock, saveclock, msgclock, paused, perfclock, cpupause;
 Mousectl *mc;
 QLock pauselock;
 u32int keys;
@@ -267,7 +267,11 @@ usage:
 			qlock(&pauselock);
 			qunlock(&pauselock);
 		}
-		t = cpustep();
+		if(cpupause){
+			t = 40;
+			cpupause = 0;
+		}else
+			t = cpustep();
 		spcclock -= t;
 		stimerclock += t;
 		ppuclock += t;