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games/snes: made cpu timing slightly more accurate

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This commit is contained in:
aiju 2014-03-20 16:44:01 +01:00
parent 3a54967108
commit 4b0467ce44
3 changed files with 23 additions and 4 deletions
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2
sys/src/games/snes/dat.h
View file

@ -6,6 +6,7 @@ extern u32int rPB, curpc;
extern u8int dma, nmi, irq;
extern u32int hdma;
extern int trace;
extern int memcyc;
extern uchar *prg, *sram;
extern int nprg, nsram, hirom;
@ -66,6 +67,7 @@ enum {
OVERSCAN = 1<<2,
AUTOJOY = 1,
NMITIMEN = 0x4200,
MEMSEL = 0x420d,
RDNMI = 0x4210,
VBLANK = 1<<7,
VCNTIRQ = 1<<5,

18
sys/src/games/snes/mem.c
View file

@ -10,6 +10,7 @@ u8int oam[544], vram[65536];
u16int cgram[256];
u16int oamaddr, vramlatch;
u32int keylatch, lastkeys;
int memcyc;
enum {
OAMLATCH,
CGLATCH,
@ -373,11 +374,18 @@ memread(u32int a)
return sram[(b << 13 | al & 0x1ffff) & (nsram - 1)];
return regread(al);
}
if(!hirom && (b & 0xf8) == 0x70 && nsram != 0)
if(!hirom && (b & 0xf8) == 0x70 && nsram != 0){
if(a < 0x800000 || (reg[MEMSEL] & 1) == 0)
memcyc += 2;
return sram[a & 0x07ffff & (nsram - 1)];
}
}
if(b >= 0x7e && (a & (1<<23)) == 0)
if(b >= 0x7e && (a & (1<<23)) == 0){
memcyc += 2;
return mem[a - 0x7e0000];
}
if(a < 0x800000 || (reg[MEMSEL] & 1) == 0)
memcyc += 2;
if(hirom)
return prg[((b & 0x3f) % nprg) << 16 | al];
return prg[(b%nprg) << 15 | al & 0x7fff];
@ -391,8 +399,10 @@ memwrite(u32int a, u8int v)
al = a;
b = (a>>16) & 0x7f;
if(b >= 0x7e && a < 0x800000)
if(b >= 0x7e && a < 0x800000){
memcyc += 2;
mem[a - 0x7e0000] = v;
}
if(al < 0x8000){
if(b < 0x40){
if(hirom && al >= 0x6000 && nsram != 0){
@ -405,6 +415,8 @@ memwrite(u32int a, u8int v)
if(!hirom && (b & 0xf8) == 0x70 && nsram != 0){
sram[a & 0x07ffff & (nsram - 1)] = v;
save:
if(a < 0x800000 || (reg[MEMSEL] & 1) == 0)
memcyc += 2;
if(saveclock == 0)
saveclock = SAVEFREQ;
return;

7
sys/src/games/snes/snes.c
View file

@ -255,7 +255,12 @@ usage:
qlock(&pauselock);
qunlock(&pauselock);
}
t = cpustep() * 8;
memcyc = 0;
t = cpustep();
if(curpc == -1)
t *= 8;
else
t = t * 6 + memcyc;
spcclock -= t;
stimerclock += t;
ppuclock += t;