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Bit 0 of port 3da on Amstrad PC1512 is a toggle bit instead of display enable.

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This commit is contained in:
SarahW 2020-02-18 12:08:53 +00:00
commit 32563970c2
1 changed files with 2 additions and 4 deletions
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6
src/vid_pc1512.c
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@ -107,7 +107,8 @@ static uint8_t pc1512_in(uint16_t addr, void *p)
case 0x3d5: case 0x3d5:
return pc1512->crtc[pc1512->crtcreg]; return pc1512->crtc[pc1512->crtcreg];
case 0x3da: case 0x3da:
return pc1512->stat; pc1512->stat ^= 0x01; /*Bit 0 is toggle bit on PC1512*/
return pc1512->stat ^ 0x01;
} }
return 0xff; return 0xff;
} }
@ -174,7 +175,6 @@ static void pc1512_poll(void *p)
if (!pc1512->linepos) if (!pc1512->linepos)
{ {
timer_advance_u64(&pc1512->timer, pc1512->dispofftime); timer_advance_u64(&pc1512->timer, pc1512->dispofftime);
pc1512->stat |= 1;
pc1512->linepos = 1; pc1512->linepos = 1;
oldsc = pc1512->sc; oldsc = pc1512->sc;
if (pc1512->dispon) if (pc1512->dispon)
@ -342,8 +342,6 @@ static void pc1512_poll(void *p)
timer_advance_u64(&pc1512->timer, pc1512->dispontime); timer_advance_u64(&pc1512->timer, pc1512->dispontime);
if ((pc1512->lastline - pc1512->firstline) == 199) if ((pc1512->lastline - pc1512->firstline) == 199)
pc1512->dispon = 0; /*Amstrad PC1512 always displays 200 lines, regardless of CRTC settings*/ pc1512->dispon = 0; /*Amstrad PC1512 always displays 200 lines, regardless of CRTC settings*/
if (pc1512->dispon)
pc1512->stat &= ~1;
pc1512->linepos = 0; pc1512->linepos = 0;
if (pc1512->vsynctime) if (pc1512->vsynctime)
{ {