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Rework (S)VGA memory addressing. Support correct chain-4 mapping, as well

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as MA13/14 remapping for non-CGA modes. Fixes corruption on Windows 3.x
when using Paradise drivers, also fixes corruption in Titan.
This commit is contained in:
SarahW 2021-05-29 09:08:34 +01:00
commit 092be3e9d4
12 changed files with 740 additions and 239 deletions
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17
src/vid_cl5429.c
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@ -1,4 +1,5 @@
/*Cirrus Logic CL-GD5429 emulation*/
//SR7.0 = "true packed-pixel memory addressing"
#include <stdlib.h>
#include "ibm.h"
#include "cpu.h"
@ -178,6 +179,8 @@ void gd5429_out(uint16_t addr, uint8_t val, void *p)
case 0x07:
svga->set_reset_disabled = svga->seqregs[7] & 1;
svga->packed_chain4 = svga->seqregs[7] & 1;
svga_recalctimings(svga);
case 0x17:
if (gd5429->type >= CL_TYPE_GD5429)
gd5429_recalc_mapping(gd5429);
@ -844,11 +847,16 @@ void gd5429_write_linear(uint32_t addr, uint8_t val, void *p)
svga->fullchange = 2;
if (svga->gdcreg[0xb] & GRB_X8_ADDRESSING)
addr <<= 3;
else if ((svga->chain4 || svga->fb_only) && (svga->writemode < 4))
else if (((svga->chain4 && svga->packed_chain4) || svga->fb_only) && (svga->writemode < 4))
{
writemask2 = 1 << (addr & 3);
addr &= ~3;
}
else if (svga->chain4)
{
writemask2 = 1 << (addr & 3);
addr = ((addr & 0xfffc) << 2) | ((addr & 0x30000) >> 14) | (addr & ~0x3ffff);
}
else if (svga->chain2_write)
{
writemask2 &= ~0xa;
@ -1193,13 +1201,18 @@ uint8_t gd5429_read_linear(uint32_t addr, void *p)
if (svga->gdcreg[0xb] & GRB_X8_ADDRESSING)
addr <<= 3;
else if (svga->chain4 || svga->fb_only)
else if ((svga->chain4 && svga->packed_chain4) || svga->fb_only)
{
addr &= svga->decode_mask;
if (addr >= svga->vram_max)
return 0xff;
return svga->vram[addr & svga->vram_mask];
}
else if (svga->chain4)
{
readplane = addr & 3;
addr = ((addr & 0xfffc) << 2) | ((addr & 0x30000) >> 14) | (addr & ~0x3ffff);
}
else if (svga->chain2_read)
{
readplane = (readplane & 2) | (addr & 1);