Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fixed CGA graphics modes on VGA cards

Browse source
This commit is contained in:
Jeff Parsons 2016-03-12 13:33:21 -08:00
commit 0eddbd05a3
60 changed files with 6775 additions and 404 deletions
Download patch file Download diff file Expand all files Collapse all files

23
modules/pcjs/lib/video.js
View file

@ -4893,8 +4893,10 @@ Video.prototype.checkMode = function(fForce)
* from increasingly greater EGA support to increasingly greater VGA support. Make it more rational someday,
* so that as support is added for even more modes (eg, "Mode X" variations, monochrome modes, etc), it
* doesn't get totally out of control.
*
* One of the problems with the current approach is that it depends on the card's registers being programmed
* in at least roughly the same order that the IBM EGA and VGA ROMs program them.
*/
var fSEQDotClock, nCRTCVertTotal, nCRTCMaxScan;
var regGRCMode = card.regGRCData[Card.GRC.MODE.INDX];
/*
@ -4916,13 +4918,16 @@ Video.prototype.checkMode = function(fForce)
}
}
fSEQDotClock = (card.regSEQData[Card.SEQ.CLOCKING.INDX] & Card.SEQ.CLOCKING.DOTCLOCK);
nCRTCVertTotal = card.regCRTData[Card.CRTC.EGA.VTOTAL];
var fSEQDotClock = (card.regSEQData[Card.SEQ.CLOCKING.INDX] & Card.SEQ.CLOCKING.DOTCLOCK);
var nCRTCVertTotal = card.regCRTData[Card.CRTC.EGA.VTOTAL];
nCRTCVertTotal |= ((card.regCRTData[Card.CRTC.EGA.OVERFLOW.INDX] & Card.CRTC.EGA.OVERFLOW.VTOTAL_BIT8)? 0x100 : 0);
if (card.nCard == Video.CARD.VGA) {
nCRTCVertTotal |= ((card.regCRTData[Card.CRTC.EGA.OVERFLOW.INDX] & Card.CRTC.EGA.OVERFLOW.VTOTAL_BIT9)? 0x200 : 0);
}
nCRTCMaxScan = card.regCRTData[Card.CRTC.EGA.MAX_SCAN.INDX];
var nCRTCMaxScan = card.regCRTData[Card.CRTC.EGA.MAX_SCAN.INDX];
var nCRTCModeCtrl = card.regCRTData[Card.CRTC.EGA.MODE_CTRL.INDX];
if (nMode != Video.MODE.UNKNOWN) {
if (!(regGRCMisc & Card.GRC.MISC.GRAPHICS)) {
@ -4933,16 +4938,16 @@ Video.prototype.checkMode = function(fForce)
*/
nMode -= (fSEQDotClock? 2 : 0);
}
else if (card.addrBuffer != 0xA0000 && !fTextGraphicsHybrid && nCRTCVertTotal < 350) {
else if (card.addrBuffer != 0xA0000 && !fTextGraphicsHybrid && !(nCRTCModeCtrl & Card.CRTC.EGA.MODE_CTRL.COMPAT_MODE)) {
/*
* Here's where we handle CGA graphics modes; since nMode will have been assigned a
* default of either 0x02 or 0x03, convert that to either 0x05 or 0x04 if we're in a
* low-res graphics mode, 0x06 otherwise.
*
* For Windows 95, I've had to add BOTH the "!fTextGraphicsHybrid" test (to avoid
* misdetecting the logo display mode) AND the "nCRTCVertTotal < 350" test (to avoid
* misinterpreting the VDD's video reprogramming during VM creation, the purpose of
* which is still a mystery to me).
* For Windows 95, I've had to add BOTH the fTextGraphicsHybrid test, to avoid misdetecting
* the logo display mode, AND the COMPAT_MODE test, to avoid misinterpreting the VDD's physical
* (NOT logical) card reprogramming during windowed VM creation; the latter seems like a VDD bug,
* because only the Windows display driver should be *physically* reprogramming the card then.
*/
nMode = fSEQDotClock? (7 - nMode) : Video.MODE.CGA_640X200;
} else {