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Merge pull request #269 from MoochMcGee/master

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Add more accurate CGA waitstates
This commit is contained in:
OBattler
2018-03-10 16:47:47 +01:00
committed by GitHub
parent 7fc3629f51 c1cb892c09
commit 07035f7100
1 changed files with 16 additions and 2 deletions
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18
src/video/vid_cga.c
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@@ -106,6 +106,20 @@ uint8_t cga_in(uint16_t addr, void *p)
return 0xFF; return 0xFF;
} }
void cga_waitstates(void *p)
{
cga_t *cga = (cga_t *)p;
int cycle = ((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST));
cycles -= 8 - (cycle & 7);
cycle = ((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST));
cycles -= 16 - (cycle & 15);
cycle = ((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST));
cycles -= 3 - (cycle % 3);
}
void cga_write(uint32_t addr, uint8_t val, void *p) void cga_write(uint32_t addr, uint8_t val, void *p)
{ {
cga_t *cga = (cga_t *)p; cga_t *cga = (cga_t *)p;
@@ -117,13 +131,13 @@ void cga_write(uint32_t addr, uint8_t val, void *p)
cga->charbuffer[(((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST)) & 0xfc) | 1] = val; cga->charbuffer[(((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST)) & 0xfc) | 1] = val;
} }
egawrites++; egawrites++;
cycles -= 4; cga_waitstates(cga);
} }
uint8_t cga_read(uint32_t addr, void *p) uint8_t cga_read(uint32_t addr, void *p)
{ {
cga_t *cga = (cga_t *)p; cga_t *cga = (cga_t *)p;
cycles -= 4; cga_waitstates(cga);
if (cga->snow_enabled) if (cga->snow_enabled)
{ {
cga->charbuffer[ ((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST)) & 0xfc] = cga->vram[addr & 0x3fff]; cga->charbuffer[ ((int)(((cga->dispontime - cga->vidtime) * 2) / CGACONST)) & 0xfc] = cga->vram[addr & 0x3fff];