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

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(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
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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_old = svga->hdisp;
switch (svga->gdcreg[5] & 0x60) {
case 0x00:
if (svga->bpp <= 8) {
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)*/
svga->render = svga_render_4bpp_lowres;
else
svga->render = svga_render_4bpp_highres;
break;
case 0x20: /*4 colours*/
if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->render = svga_render_2bpp_lowres;
else
svga->render = svga_render_2bpp_highres;
break;
case 0x40:
case 0x60: /*256+ colours*/
switch (svga->bpp) {
case 8:
svga->map8 = svga->pallook;
if (svga->lowres)
svga->render = svga_render_8bpp_lowres;
else
svga->render = svga_render_8bpp_highres;
break;
case 15:
if (svga->lowres)
svga->render = svga_render_15bpp_lowres;
else
svga->render = svga_render_15bpp_highres;
break;
case 16:
if (svga->lowres)
svga->render = svga_render_16bpp_lowres;
else
svga->render = svga_render_16bpp_highres;
break;
case 17:
if (svga->lowres)
svga->render = svga_render_15bpp_mix_lowres;
else
svga->render = svga_render_15bpp_mix_highres;
break;
case 24:
if (svga->lowres)
svga->render = svga_render_24bpp_lowres;
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;
}
} else {
switch (svga->gdcreg[5] & 0x60) {
case 0x00:
if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->render = svga_render_4bpp_lowres;
else
svga->render = svga_render_4bpp_highres;
break;
case 0x20: /*4 colours*/
if (svga->seqregs[1] & 8) /*Low res (320)*/
svga->render = svga_render_2bpp_lowres;
else
svga->render = svga_render_2bpp_highres;
break;
case 0x40:
case 0x60: /*256+ colours*/
switch (svga->bpp) {
case 8:
svga->map8 = svga->pallook;
if (svga->lowres)
svga->render = svga_render_8bpp_lowres;
else
svga->render = svga_render_8bpp_highres;
break;
case 15:
if (svga->lowres)
svga->render = svga_render_15bpp_lowres;
else
svga->render = svga_render_15bpp_highres;
break;
case 16:
if (svga->lowres)
svga->render = svga_render_16bpp_lowres;
else
svga->render = svga_render_16bpp_highres;
break;
case 17:
if (svga->lowres)
svga->render = svga_render_15bpp_mix_lowres;
else
svga->render = svga_render_15bpp_mix_highres;
break;
case 24:
if (svga->lowres)
svga->render = svga_render_24bpp_lowres;
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:
break;
}
break;
default:
break;
}
break;
default:
break;
default:
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 *p;
uint8_t edat[4];
uint8_t dat;
uint32_t changed_offset;
const bool blinked = svga->blink & 0x10;
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.
// But on an S3 Trio, mode 13h is broken - seemingly accepting the address shift but ignoring the increment.
// Forcing it to use incbypow2=0, incevery=1, loadevery=1 makes it behave.
// But on some cards, certain modes are broken.
// - 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 wordload = ((svga->seqregs[0x01] & 0x04) != 0) && !dwordload;
const bool wordincr = ((svga->crtc[0x17] & 0x08) != 0);
const bool dwordincr = ((svga->crtc[0x14] & 0x20) != 0) && !wordincr;
const bool dwordshift = ((svga->crtc[0x14] & 0x40) != 0);
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 incevery = (combine8bits && (svga->force_old_addr || svga->packed_chain4)) ? 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 incbypow2 = forcepacked ? 0 : (dwordshift ? 2 : wordshift ? 1 : 0);
const uint32_t incevery = forcepacked ? 1 : (dwordincr ? 4 : wordincr ? 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 );
const bool shift4bit = ((svga->gdcreg[0x05] & 0x40) == 0x40 ) || highres8bpp;
const bool shift2bit = ((svga->gdcreg[0x05] & 0x60) == 0x20 ) && !shift4bit;
const int dwshift = highres ? 0 : 1;
const int dotwidth = 1 << dwshift;