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Mode X test passes

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This commit is contained in:
Jeff Parsons 2015-07-06 17:11:01 -07:00
commit 6d7000935c
1 changed files with 21 additions and 15 deletions
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36
modules/pcjs/lib/video.js
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@ -1177,14 +1177,14 @@ Card.CRTC = {
VBLANK_END: 0x16,
MODE_CTRL: {
INDX: 0x17,
CMS: 0x01, // Compatibility Mode Support (CGA A13 control)
SRSC: 0x02, // Select Row Scan Counter
HRS: 0x04, // Horizontal Retrace Select
CBT: 0x08, // Count By Two
OC: 0x10, // Output Control
AW: 0x20, // Address Wrap (in Word mode, 1 maps A15 to A0 and 0 maps A13; use the latter when only 64Kb is installed)
BM: 0x40, // Byte Mode (1 selects Byte Mode; 0 selects Word Mode)
HR: 0x80 // Hardware Reset
COMPAT_MODE: 0x01, // Compatibility Mode Support (CGA A13 control)
SEL_ROW_SCAN: 0x02, // Select Row Scan Counter
SEL_HRETRACE: 0x04, // Horizontal Retrace Select
COUNTBY2: 0x08, // Count By Two
OUTPUT_CTRL: 0x10, // Output Control
ADDR_WRAP: 0x20, // Address Wrap (in Word mode, 1 maps A15 to A0 and 0 maps A13; use the latter when only 64Kb is installed)
BYTE_MODE: 0x40, // Byte Mode (1 selects Byte Mode; 0 selects Word Mode)
HARD_RESET: 0x80 // Hardware Reset
},
LINE_COMPARE: 0x18,
TOTAL_REGS: 0x19 // total CRT registers on EGA/VGA
@ -1562,11 +1562,11 @@ if (DEBUGGER) Card.GRC.REGS = ["SRESET","ESRESET","COLORCMP","DATAROT","READMAP"
* Even/Odd Memory Access Functions
*
* The "EVENODD" functions deal with the EGA's default text-mode addressing, where EVEN addresses are mapped to
* plane 0 (and 2) and ODD addresses are mapped to plane 1 (and 3). This occurs when SEQ.MEMMODE.SEQUENTIAL
* is clear (and GRC.MODE.EVENODD is set), turning address bit 0 (A0) into a "plane select" bit. Whether A0 is
* also used as a memory address bit depends on CRTC.MODE_CTRL.BM: if it's set, then we're in "Byte Mode" and A0 is
* used as-is; if it's clear, then we're in "Word Mode", and either A15 (when CRTC.MODE_CTRL.AW is set) or A13
* (when CRTC.MODE_CTRL.AW is clear, typically when only 64Kb of EGA memory is installed) is substituted for A0.
* plane 0 (and 2) and ODD addresses are mapped to plane 1 (and 3). This occurs when SEQ.MEMMODE.SEQUENTIAL is
* clear (and GRC.MODE.EVENODD is set), turning address bit 0 (A0) into a "plane select" bit. Whether A0 is also
* used as a memory address bit depends on CRTC.MODE_CTRL.BYTE_MODE: if it's set, then we're in "Byte Mode" and A0 is
* used as-is; if it's clear, then we're in "Word Mode", and either A15 (when CRTC.MODE_CTRL.ADDR_WRAP is set) or A13
* (when CRTC.MODE_CTRL.ADDR_WRAP is clear, typically when only 64Kb of EGA memory is installed) is substituted for A0.
*
* Note that A13 remains clear until addresses reach 8K, at which point we've spanned 32Kb of EGA memory, so it makes
* sense to propagate A13 to A0 at that point, so that the next 8K of addresses start using ODD instead of EVEN bytes,
@ -5002,7 +5002,7 @@ Video.prototype.updateScreen = function(fForce)
* cbScreen was computed (but without any CGA-related padding considerations).
*
* TODO: I'm taking a lot of shortcuts in this calculation (eg, relying on nFont to detect text modes,
* ignoring MODE_CTRL.BM, etc); generalize this someday.
* ignoring MODE_CTRL.BYTE_MODE, etc); generalize this someday.
*/
this.nColsLogical = card.regCRTData[Card.CRTC.EGA.OFFSET] << (this.nFont? 1 : (card.regCRTData[Card.CRTC.EGA.UNDERLINE.INDX] & Card.CRTC.EGA.UNDERLINE.DWORD)? 3 : 4);
cbScreen = ((this.nColsLogical * (this.nRows-1) + this.nCols) / this.nCellsPerWord)|0;
@ -6373,8 +6373,14 @@ Video.prototype.outCRTCData = function(card, port, bOut, addrFrom)
* On the other hand, if this was an out-of-sequence write to Card.CRTC.MAX_SCAN.INDX, then
* yes, we want to force setMode() to call setDimensions(), which is key to setting the proper
* number of screen rows.
*
* The second part of the check is required to promptly detect a switch to "Mode X"; if we assume
* that anyone switching to "Mode X" will first switch to mode 0x13, then it's a given that they
* must reprogram the VDISP_END register, and that they will change it from 0x8F to 0xDF. However,
* I'm not going to make the test that restrictive, to help ensure I catch minor variations to
* "Mode X", at the expense of triggering potentially unnecessary calls to checkMode().
*/
if (card.regCRTIndx == Card.CRTC.MAX_SCAN.INDX && card.regCRTPrev != Card.CRTC.MAX_SCAN.INDX-1) {
if (card.regCRTIndx == Card.CRTC.MAX_SCAN.INDX && card.regCRTPrev != Card.CRTC.MAX_SCAN.INDX-1 || card.regCRTIndx == Card.CRTC.EGA.VDISP_END) {
this.checkMode(true);
}
this.checkCursor();