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Support video buffers with a logical width greater than the visible width

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This commit is contained in:
Jeff Parsons 2015-06-16 17:14:49 -07:00
commit 7491ee6332
1 changed files with 20 additions and 14 deletions
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34
modules/pcjs/lib/video.js
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@ -122,11 +122,11 @@ function Video(parmsVideo, canvas, context, textarea, container)
/*
* setDimensions() uses these values ONLY if it doesn't recognize the video mode.
*/
this.nDefaultCols = parmsVideo['charCols'];
this.nDefaultRows = parmsVideo['charRows'];
if (this.nDefaultCols === undefined || this.nDefaultRows === undefined) {
this.nDefaultCols = Video.aModeParms[this.nModeDefault][0];
this.nDefaultRows = Video.aModeParms[this.nModeDefault][1];
this.nColsDefault = parmsVideo['charCols'];
this.nRowsDefault = parmsVideo['charRows'];
if (this.nColsDefault === undefined || this.nRowsDefault === undefined) {
this.nColsDefault = Video.aModeParms[this.nModeDefault][0];
this.nRowsDefault = Video.aModeParms[this.nModeDefault][1];
}
/*
@ -142,7 +142,7 @@ function Video(parmsVideo, canvas, context, textarea, container)
* the default FONT cell size.
*/
this.fScaleFont = parmsVideo['scale'];
this.fDoubleFont = Math.round(this.cxScreen / this.nDefaultCols) >= 12;
this.fDoubleFont = Math.round(this.cxScreen / this.nColsDefault) >= 12;
this.fTouchScreen = parmsVideo['touchScreen'];
@ -4011,8 +4011,9 @@ Video.prototype.setAccess = function(nAccess)
Video.prototype.setDimensions = function()
{
this.nFont = 0;
this.nCols = this.nDefaultCols;
this.nRows = this.nDefaultRows;
this.nCols = this.nColsDefault;
this.nRows = this.nRowsDefault;
this.nColsLogical = this.nCols;
this.nCellsPerWord = Video.aModeParms[Video.MODE.MDA_80X25][2];
this.cbPadding = 0;
@ -4690,9 +4691,8 @@ Video.prototype.updateScreen = function(fForce)
* We now calculate the logical width, and the compute a new cbScreen in much the same way the
* original cbScreen was computed (but without any CGA-related padding considerations).
*/
var nCols = this.cardActive.regCRTData[Card.CRTC.EGA.OFFSET] << (this.nFont? 1 : 4);
cbScreen = ((((nCols * this.nRows) / this.nCellsPerWord) << 1) + this.cbPadding)|0;
this.assert(cbScreen === this.cbScreen);
this.nColsLogical = this.cardActive.regCRTData[Card.CRTC.EGA.OFFSET] << (this.nFont? 1 : 4);
cbScreen = ((((this.nColsLogical * this.nRows) / this.nCellsPerWord) << 1) + this.cbPadding)|0;
}
if (addrScreen + cbScreen > addrScreenLimit) {
@ -4927,9 +4927,9 @@ Video.prototype.updateScreenGraphicsEGA = function(addrScreen, addrScreenLimit)
*/
var dwPixel = data & (0x80808080|0);
/*
* This was the old fix to the above problem, which mapped any negative number to its corresponding
* positive value, without altering the low 32 bits. But it's not ideal, because it means using values
* both here and in the array that are outside the signed 32-bit range, requiring floating-point.
* This was the old approach to dealing with negative hex values, by converting them to positive
* values that didn't alter the low 32 bits. But it's not ideal, because it requires using values here
* and in the array that are outside the signed 32-bit range, potentially triggering floating-point.
*
* if (dwPixel < 0) dwPixel += 0x100000000;
*/
@ -4950,6 +4950,12 @@ Video.prototype.updateScreenGraphicsEGA = function(addrScreen, addrScreenLimit)
if (x >= this.nCols) {
x = 0;
if (++y > this.nRows) break;
if (this.nColsLogical > this.nCols) {
addr += (this.nColsLogical - this.nCols) >> 3;
}
/*
* TODO: What should happen if the card is programmed such that nColsLogical is LESS THAN nCols?
*/
}
}
/*