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Mask off accesses to SDAC extended registers. Fixes out-of-bounds register writes causing corruption seen sometimes in Windows 95.

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This commit is contained in:
SarahW 2017-10-25 20:53:32 +01:00
commit 7d484e0928
1 changed files with 4 additions and 4 deletions
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8
src/vid_sdac_ramdac.c
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@ -50,8 +50,8 @@ void sdac_ramdac_out(uint16_t addr, uint8_t val, sdac_ramdac_t *ramdac, svga_t *
ramdac->magic_count = 0;
if (ramdac->rs2)
{
if (!ramdac->reg_ff) ramdac->regs[ramdac->windex] = (ramdac->regs[ramdac->windex] & 0xff00) | val;
else ramdac->regs[ramdac->windex] = (ramdac->regs[ramdac->windex] & 0x00ff) | (val << 8);
if (!ramdac->reg_ff) ramdac->regs[ramdac->windex & 0xff] = (ramdac->regs[ramdac->windex & 0xff] & 0xff00) | val;
else ramdac->regs[ramdac->windex & 0xff] = (ramdac->regs[ramdac->windex & 0xff] & 0x00ff) | (val << 8);
ramdac->reg_ff = !ramdac->reg_ff;
// pclog("RAMDAC reg %02X now %04X\n", ramdac->windex, ramdac->regs[ramdac->windex]);
if (!ramdac->reg_ff) ramdac->windex++;
@ -106,8 +106,8 @@ uint8_t sdac_ramdac_in(uint16_t addr, sdac_ramdac_t *ramdac, svga_t *svga)
// }
if (ramdac->rs2)
{
if (!ramdac->reg_ff) temp = ramdac->regs[ramdac->rindex] & 0xff;
else temp = ramdac->regs[ramdac->rindex] >> 8;
if (!ramdac->reg_ff) temp = ramdac->regs[ramdac->rindex & 0xff] & 0xff;
else temp = ramdac->regs[ramdac->rindex & 0xff] >> 8;
ramdac->reg_ff = !ramdac->reg_ff;
if (!ramdac->reg_ff)
{