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Fix latching in svga_read_linear(). Fixes Jazz Jackrabbit on Cirrus Logic cards.

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This commit is contained in:
SarahW 2019-12-20 17:01:53 +00:00
commit f56f5e76e6
1 changed files with 14 additions and 4 deletions
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18
src/vid_svga.c
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@ -1229,6 +1229,7 @@ uint8_t svga_read_linear(uint32_t addr, void *p)
svga_t *svga = (svga_t *)p;
uint8_t temp, temp2, temp3, temp4;
int readplane = svga->readplane;
uint32_t latch_addr = (addr << 2) & svga->decode_mask;
cycles -= video_timing_read_b;
cycles_lost += video_timing_read_b;
@ -1253,15 +1254,24 @@ uint8_t svga_read_linear(uint32_t addr, void *p)
addr &= svga->decode_mask;
if (latch_addr >= svga->vram_max)
{
svga->la = svga->lb = svga->lc = svga->ld = 0xff;
}
else
{
latch_addr &= svga->vram_mask;
svga->la = svga->vram[latch_addr];
svga->lb = svga->vram[latch_addr | 0x1];
svga->lc = svga->vram[latch_addr | 0x2];
svga->ld = svga->vram[latch_addr | 0x3];
}
if (addr >= svga->vram_max)
return 0xff;
addr &= svga->vram_mask;
svga->la = svga->vram[addr];
svga->lb = svga->vram[addr | 0x1];
svga->lc = svga->vram[addr | 0x2];
svga->ld = svga->vram[addr | 0x3];
if (svga->readmode)
{
temp = svga->la;