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gba: handle 8bit writes to vram

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ignore 8bit writes to obj and oam, and duplicate bits for bg and palette
memory, as per gbatek.

thanks aiju for helping with the implementation.
This commit is contained in:
qwx 2018-06-22 14:49:18 +02:00
parent f554155ed0
commit 0da9e3a7f5
1 changed files with 14 additions and 2 deletions
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16
sys/src/games/gba/mem.c
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@ -315,6 +315,11 @@ memwrite(u32int a, u32int v, int n)
return;
case 5:
b = a & sizeof(pram) - 1;
if(n == 1){
b &= ~1;
n = 2;
v |= v << 8;
}
cyc += (n+1) >> 1;
ar16write(pram + b/2, b & 1, v, n);
return;
@ -322,13 +327,20 @@ memwrite(u32int a, u32int v, int n)
b = a & 128*KB - 1;
if(b >= 64*KB)
b &= ~(32*KB);
if(n == 1 && ((reg[DISPCNT] & 7) > 2 && b < 80*KB || b < 64*KB)){
b &= ~1;
n = 2;
v |= v << 8;
}
cyc += (n+1) >> 1;
arwrite(vram + b, v, n);
if(n != 1)
arwrite(vram + b, v, n);
return;
case 7:
b = a & sizeof(oam) - 1;
cyc++;
ar16write(oam + b/2, b & 1, v, n);
if(n != 1)
ar16write(oam + b/2, b & 1, v, n);
return;
case 8: case 9: case 10: case 11: case 12: case 13:
if(backup == EEPROM){