pcem/src/vid_ati68860_ramdac.c
TomW 8cd1b2d29c Mach64 changes :
No longer implements CRTC registers beyond 0x18 - NT no longer detects ET4000.
RGBA8888 mode supported - fixes NT 32-bit colour mode.
Bit order controls supported for CPU 1-bit data - fixes NT 24-bit colour mode.
2014-07-24 21:30:17 +01:00

121 lines
4 KiB
C

/*ATI 68860 RAMDAC emulation (for Mach64)*/
/*
ATI 68860/68880 Truecolor DACs:
REG08 (R/W):
bit 0-? Always 2 ??
REG0A (R/W):
bit 0-? Always 1Dh ??
REG0B (R/W): (GMR ?)
bit 0-7 Mode. 82h: 4bpp, 83h: 8bpp, A0h: 15bpp, A1h: 16bpp, C0h: 24bpp,
E3h: 32bpp (80h for VGA modes ?)
REG0C (R/W): Device Setup Register A
bit 0 Controls 6/8bit DAC. 0: 8bit DAC/LUT, 1: 6bit DAC/LUT
2-3 Depends on Video memory (= VRAM width ?) . 1: Less than 1Mb, 2: 1Mb,
3: > 1Mb
5-6 Always set ?
7 If set can remove "snow" in some cases (A860_Delay_L ?) ??
*/
#include "ibm.h"
#include "mem.h"
#include "video.h"
#include "vid_svga.h"
#include "vid_ati68860_ramdac.h"
#include "vid_svga_render.h"
void ati68860_ramdac_out(uint16_t addr, uint8_t val, ati68860_ramdac_t *ramdac, svga_t *svga)
{
// pclog("ati68860_out : addr %04X val %02X %04X:%04X\n", addr, val, CS,pc);
switch (addr)
{
case 0:
svga_out(0x3c8, val, svga);
break;
case 1:
svga_out(0x3c9, val, svga);
break;
case 2:
svga_out(0x3c6, val, svga);
break;
case 3:
svga_out(0x3c7, val, svga);
break;
default:
ramdac->regs[addr & 0xf] = val;
switch (addr & 0xf)
{
case 0xb:
switch (val)
{
case 0x82:
ramdac->render = svga_render_4bpp_highres;
break;
case 0x83:
ramdac->render = svga_render_8bpp_highres;
break;
case 0xa0:
ramdac->render = svga_render_15bpp_highres;
break;
case 0xa1: case 0xb1:
ramdac->render = svga_render_16bpp_highres;
break;
case 0xc0: case 0xd0:
ramdac->render = svga_render_24bpp_highres;
break;
case 0xe2:
ramdac->render = svga_render_32bpp_highres;
break;
case 0xf2:
ramdac->render = svga_render_RGBA8888_highres;
break;
default:
ramdac->render = svga_render_8bpp_highres;
break;
}
break;
}
break;
}
}
uint8_t ati68860_ramdac_in(uint16_t addr, ati68860_ramdac_t *ramdac, svga_t *svga)
{
uint8_t ret = 0;
switch (addr)
{
case 0:
ret = svga_in(0x3c8, svga);
break;
case 1:
ret = svga_in(0x3c9, svga);
break;
case 2:
ret = svga_in(0x3c6, svga);
break;
case 3:
ret = svga_in(0x3c7, svga);
break;
case 4: case 8:
ret = 2;
break;
case 6: case 0xa:
ret = 0x1d;
break;
case 0xf:
ret = 0xd0;
break;
default:
ret = ramdac->regs[addr & 0xf];
break;
}
// pclog("ati68860_in : addr %04X ret %02X %04X:%04X\n", addr, ret, CS,pc);
return ret;
}
void ati68860_ramdac_init(ati68860_ramdac_t *ramdac)
{
ramdac->render = svga_render_8bpp_highres;
}