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Improved masking of (S)VGA read/write addresses.

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This commit is contained in:
OBattler
2016-10-08 04:20:30 +02:00
parent 904d75079f
commit ce6bfd4e67
2 changed files with 80 additions and 48 deletions
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40
src/vid_svga.c
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@@ -592,6 +592,10 @@ uint32_t svga_mask_addr(uint32_t addr, svga_t *svga)
{
limit_shift = 1;
}
if ((svga->gdcreg[5] & 0x60) == 0x20)
{
limit_shift = 1;
}
if (svga->vrammask == (svga->vram_limit - 1))
{
return addr % (svga->vram_limit >> limit_shift);
@@ -602,6 +606,18 @@ uint32_t svga_mask_addr(uint32_t addr, svga_t *svga)
}
}
uint32_t svga_mask_changedaddr(uint32_t addr, svga_t *svga)
{
if (svga->vrammask == (svga->vram_limit - 1))
{
return addr % (svga->vram_limit >> 12);
}
else
{
return addr & (svga->vrammask >> 12);
}
}
void svga_poll(void *p)
{
svga_t *svga = (svga_t *)p;
@@ -978,6 +994,8 @@ void svga_write(uint32_t addr, uint8_t val, void *p)
if (addr >= svga->vram_limit)
return;
addr = svga_mask_addr(addr, svga);
if (svga_output) pclog("%08X (%i, %i) %02X %i %i %i %02X\n", addr, addr & 1023, addr >> 10, val, writemask2, svga->writemode, svga->chain4, svga->gdcreg[8]);
svga->changedvram[addr >> 12] = changeframecount;
@@ -1147,7 +1165,8 @@ uint8_t svga_read(uint32_t addr, void *p)
addr &= svga->banked_mask;
addr += svga->read_bank;
latch_addr = (addr << 2) % svga->vram_limit;
// latch_addr = (addr << 2) % svga->vram_limit;
latch_addr = svga_mask_addr(addr << 2);
// latch_addr = (addr << 2);
// pclog("%05X %i %04X:%04X %02X %02X %i\n",addr,svga->chain4,CS,pc, vram[addr & 0x7fffff], vram[(addr << 2) & 0x7fffff], svga->readmode);
@@ -1157,7 +1176,7 @@ uint8_t svga_read(uint32_t addr, void *p)
// addr %= svga->vram_limit;
if (addr >= svga->vram_limit)
return 0xff;
return svga->vram[addr];
return svga->vram[svga_mask_addr(addr)];
}
else if (svga->chain2_read)
{
@@ -1172,6 +1191,8 @@ uint8_t svga_read(uint32_t addr, void *p)
if (addr >= svga->vram_limit)
return 0xff;
addr = svga_mask_addr(addr, svga);
if (latch_addr < svga->vram_limit)
{
@@ -1396,6 +1417,7 @@ uint8_t svga_read_linear(uint32_t addr, void *p)
{
svga_t *svga = (svga_t *)p;
uint8_t temp, temp2, temp3, temp4;
uint32_t latch_addr;
int readplane = svga->readplane;
cycles -= video_timing_b;
@@ -1404,13 +1426,15 @@ uint8_t svga_read_linear(uint32_t addr, void *p)
egareads++;
addr -= svga->linear_base;
latch_addr = svga_mask_addr(addr << 2);
if (svga->chain4 || svga->fb_only)
{
// addr %= svga->vram_limit;
if (addr >= svga->vram_limit)
return 0xff;
return svga->vram[addr];
return svga->vram[svga_mask_addr(addr)];
}
else if (svga->chain2_read)
{
@@ -1426,10 +1450,12 @@ uint8_t svga_read_linear(uint32_t addr, void *p)
if (addr >= svga->vram_limit)
return 0xff;
svga->la = svga->vram[addr];
svga->lb = svga->vram[addr | 0x1];
svga->lc = svga->vram[addr | 0x2];
svga->ld = svga->vram[addr | 0x3];
addr = svga_mask_addr(addr, svga);
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 (svga->readmode)
{
temp = (svga->colournocare & 1) ? 0xff : 0;