80486DX2-66/86Box-fork
1
0
Fork 0
Code Issues Pull Requests Activity

Merge pull request #3844 from iamgreaser/gm/vga-updates-20231122-001

Browse Source 
(S)VGA updates and fixes, 2023-11-22 edition
This commit is contained in:
Miran Grča
2023-11-22 22:54:29 +01:00
committed by GitHub
parent 0740f0f1cd 7de7ea3fe1
commit fbbd290c8e
2 changed files with 84 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files

125
src/video/vid_svga.c
View File

@@ -639,67 +639,82 @@ svga_recalctimings(svga_t *svga)
svga->hdisp *= (svga->seqregs[1] & 8) ? 16 : 8; svga->hdisp *= (svga->seqregs[1] & 8) ? 16 : 8;
svga->hdisp_old = svga->hdisp; svga->hdisp_old = svga->hdisp;
switch (svga->gdcreg[5] & 0x60) { if (svga->bpp <= 8) {
case 0x00: if (svga->attrregs[0x10] & 0x40) { /*8bpp mode*/
svga->map8 = svga->pallook;
if (svga->lowres) /*Low res (320)*/
svga->render = svga_render_8bpp_lowres;
else
svga->render = svga_render_8bpp_highres;
} else {
if (svga->seqregs[1] & 8) /*Low res (320)*/ if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->render = svga_render_4bpp_lowres; svga->render = svga_render_4bpp_lowres;
else else
svga->render = svga_render_4bpp_highres; svga->render = svga_render_4bpp_highres;
break; }
case 0x20: /*4 colours*/ } else {
if (svga->seqregs[1] & 8) /*Low res (320)*/ switch (svga->gdcreg[5] & 0x60) {
svga->render = svga_render_2bpp_lowres; case 0x00:
else if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->render = svga_render_2bpp_highres; svga->render = svga_render_4bpp_lowres;
break; else
case 0x40: svga->render = svga_render_4bpp_highres;
case 0x60: /*256+ colours*/ break;
switch (svga->bpp) { case 0x20: /*4 colours*/
case 8: if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->map8 = svga->pallook; svga->render = svga_render_2bpp_lowres;
if (svga->lowres) else
svga->render = svga_render_8bpp_lowres; svga->render = svga_render_2bpp_highres;
else break;
svga->render = svga_render_8bpp_highres; case 0x40:
break; case 0x60: /*256+ colours*/
case 15: switch (svga->bpp) {
if (svga->lowres) case 8:
svga->render = svga_render_15bpp_lowres; svga->map8 = svga->pallook;
else if (svga->lowres)
svga->render = svga_render_15bpp_highres; svga->render = svga_render_8bpp_lowres;
break; else
case 16: svga->render = svga_render_8bpp_highres;
if (svga->lowres) break;
svga->render = svga_render_16bpp_lowres; case 15:
else if (svga->lowres)
svga->render = svga_render_16bpp_highres; svga->render = svga_render_15bpp_lowres;
break; else
case 17: svga->render = svga_render_15bpp_highres;
if (svga->lowres) break;
svga->render = svga_render_15bpp_mix_lowres; case 16:
else if (svga->lowres)
svga->render = svga_render_15bpp_mix_highres; svga->render = svga_render_16bpp_lowres;
break; else
case 24: svga->render = svga_render_16bpp_highres;
if (svga->lowres) break;
svga->render = svga_render_24bpp_lowres; case 17:
else if (svga->lowres)
svga->render = svga_render_24bpp_highres; svga->render = svga_render_15bpp_mix_lowres;
break; else
case 32: svga->render = svga_render_15bpp_mix_highres;
if (svga->lowres) break;
svga->render = svga_render_32bpp_lowres; case 24:
else if (svga->lowres)
svga->render = svga_render_32bpp_highres; svga->render = svga_render_24bpp_lowres;
break; else
svga->render = svga_render_24bpp_highres;
break;
case 32:
if (svga->lowres)
svga->render = svga_render_32bpp_lowres;
else
svga->render = svga_render_32bpp_highres;
break;
default: default:
break; break;
} }
break; break;
default: default:
break; break;
}
} }
} }
} }

22
src/video/vid_svga_render.c
View File

@@ -455,27 +455,33 @@ svga_render_indexed_gfx(svga_t *svga, bool highres, bool combine8bits)
uint32_t addr; uint32_t addr;
uint32_t *p; uint32_t *p;
uint8_t edat[4]; uint8_t edat[4];
uint8_t dat;
uint32_t changed_offset; uint32_t changed_offset;
const bool blinked = svga->blink & 0x10; const bool blinked = svga->blink & 0x10;
const bool attrblink = ((svga->attrregs[0x10] & 0x08) != 0); const bool attrblink = ((svga->attrregs[0x10] & 0x08) != 0);
// The following is likely how it works on an IBM VGA - that is, it works with its BIOS. // The following is likely how it works on an IBM VGA - that is, it works with its BIOS.
// But on an S3 Trio, mode 13h is broken - seemingly accepting the address shift but ignoring the increment. // But on some cards, certain modes are broken.
// Forcing it to use incbypow2=0, incevery=1, loadevery=1 makes it behave. // - S3 Trio: mode 13h (320x200x8), incbypow2 given as 2 treated as 0
// - ET4000/W32i: mode 2Eh (640x480x8), incevery given as 2 treated as 1
const bool forcepacked = combine8bits && (svga->force_old_addr || svga->packed_chain4);
// SVGA cards with a high-resolution 8bpp mode may actually bypass the VGA shifter logic.
// - HT-216 (+ other Video7 chipsets?) has 0x3C4.0xC8 bit 4 which, when set to 1, loads bytes directly, bypassing the shifters.
const bool highres8bpp = combine8bits && highres;
const bool dwordload = ((svga->seqregs[0x01] & 0x10) != 0); const bool dwordload = ((svga->seqregs[0x01] & 0x10) != 0);
const bool wordload = ((svga->seqregs[0x01] & 0x04) != 0) && !dwordload; const bool wordload = ((svga->seqregs[0x01] & 0x04) != 0) && !dwordload;
const bool wordincr = ((svga->crtc[0x17] & 0x08) != 0); const bool wordincr = ((svga->crtc[0x17] & 0x08) != 0);
const bool dwordincr = ((svga->crtc[0x14] & 0x20) != 0) && !wordincr; const bool dwordincr = ((svga->crtc[0x14] & 0x20) != 0) && !wordincr;
const bool dwordshift = ((svga->crtc[0x14] & 0x40) != 0); const bool dwordshift = ((svga->crtc[0x14] & 0x40) != 0);
const bool wordshift = ((svga->crtc[0x17] & 0x40) == 0) && !dwordshift; const bool wordshift = ((svga->crtc[0x17] & 0x40) == 0) && !dwordshift;
const uint32_t incbypow2 = (combine8bits && (svga->force_old_addr || svga->packed_chain4)) ? 0 : (dwordshift ? 2 : wordshift ? 1 : 0); const uint32_t incbypow2 = forcepacked ? 0 : (dwordshift ? 2 : wordshift ? 1 : 0);
const uint32_t incevery = (combine8bits && (svga->force_old_addr || svga->packed_chain4)) ? 1 : (dwordincr ? 4 : wordincr ? 2 : 1); const uint32_t incevery = forcepacked ? 1 : (dwordincr ? 4 : wordincr ? 2 : 1);
const uint32_t loadevery = (combine8bits && (svga->force_old_addr || svga->packed_chain4)) ? 1 : (dwordload ? 4 : wordload ? 2 : 1); const uint32_t loadevery = forcepacked ? 1 : (dwordload ? 4 : wordload ? 2 : 1);
const bool shift2bit = ((svga->gdcreg[0x05] & 0x60) == 0x20 ); const bool shift4bit = ((svga->gdcreg[0x05] & 0x40) == 0x40 ) || highres8bpp;
const bool shift4bit = ((svga->gdcreg[0x05] & 0x40) == 0x40 ); const bool shift2bit = ((svga->gdcreg[0x05] & 0x60) == 0x20 ) && !shift4bit;
const int dwshift = highres ? 0 : 1; const int dwshift = highres ? 0 : 1;
const int dotwidth = 1 << dwshift; const int dotwidth = 1 << dwshift;