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games/snes: address remapping and irq reset bug fix

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This commit is contained in:
aiju 2014-03-21 12:57:17 +01:00
parent 46168ec503
commit feb800ff7c
1 changed files with 16 additions and 5 deletions
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21
sys/src/games/snes/mem.c
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@ -24,6 +24,17 @@ enum {
extern void calc7(void);
static u16int
vrammap(u16int a)
{
switch(reg[0x2115] & 12){
default: return a << 1;
case 4: return a << 1 & 0xfe00 | a << 4 & 0x01f0 | a >> 4 & 0x000e;
case 8: return a << 1 & 0xfc00 | a << 4 & 0x03f0 | a >> 5 & 0x000e;
case 12: return a << 1 & 0xf800 | a << 4 & 0x07f0 | a >> 6 & 0x000e;
}
}
static void
incvram(int i, int r)
{
@ -34,10 +45,8 @@ incvram(int i, int r)
if((c >> 7) != i)
return;
a = reg[0x2116] | reg[0x2117] << 8;
if((c & 0x0c) != 0)
print("address remapping\n");
if(r){
b = a<<1;
b = vrammap(a);
vramlatch = vram[b++];
vramlatch |= vram[b] << 8;
}
@ -254,12 +263,12 @@ regwrite(u16int p, u8int v)
v &= 0x7f;
break;
case 0x2118:
a = reg[0x2116] << 1 | reg[0x2117] << 9;
a = vrammap(reg[0x2116] | reg[0x2117] << 8);
vram[a] = v;
incvram(0, 0);
return;
case 0x2119:
a = reg[0x2116] << 1 | reg[0x2117] << 9;
a = vrammap(reg[0x2116] | reg[0x2117] << 8);
vram[a|1] = v;
incvram(1, 0);
return;
@ -306,6 +315,8 @@ regwrite(u16int p, u8int v)
case 0x4200:
if((reg[0x4200] & 0x80) == 0 && (v & 0x80) != 0 && (reg[RDNMI] & 0x80) != 0)
nmi = 2;
if((v & (HCNTIRQ|VCNTIRQ)) == 0)
irq &= ~IRQPPU;
break;
case 0x4201:
if((reg[0x4201] & 0x80) == 0 && (v & 0x80) != 0)