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Generic write mode 0 function was missing set/reset capability

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This commit is contained in:
Jeff Parsons 2015-06-27 10:31:26 -07:00
commit a0d89e5071
7 changed files with 121 additions and 112 deletions
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37
modules/pcjs/lib/video.js
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@ -1677,6 +1677,19 @@ Card.ACCESS.readByteMode1 = function readByteMode1(off, addr)
/**
* writeByteMode0(off, b, addr)
*
* Supporting Set/Reset means that for every plane for which Set/Reset is enabled, we must
* replace the corresponding byte in "dw" with a byte of zeros or ones. This is accomplished with
* nSetMapMask, nSetMapData, and nSetMapBits. nSetMapMask is the inverse of the ESRESET bits,
* because we use it to mask the processor data; nSetMapData records the desired SRESET bits; and
* nSetMapBits contains the bits to replace those that we masked in the processor data.
*
* We could have done this:
*
* dw = (dw & this.controller.nSetMapMask) | (this.controller.nSetMapData & ~this.controller.nSetMapMask)
*
* but by maintaining nSetMapBits equal to (nSetMapData & ~nSetMapMask), we are able to make the writes
* slightly more efficient.
*
* @this {Memory}
* @param {number} off
* @param {number} b (which should already be pre-masked to 8 bits; see Bus.prototype.setByteDirect)
@ -1686,7 +1699,8 @@ Card.ACCESS.writeByteMode0 = function writeByteMode0(off, b, addr)
{
var idw = off + this.offset;
var dw = b | (b << 8) | (b << 16) | (b << 24);
dw = (this.adw[idw] & ~this.controller.nWriteMapMask) | (dw & this.controller.nWriteMapMask);
dw = (dw & this.controller.nSetMapMask) | this.controller.nSetMapBits;
dw = (dw & this.controller.nWriteMapMask) | (this.adw[idw] & ~this.controller.nWriteMapMask);
dw = (dw & this.controller.nBitMapMask) | (this.controller.latches & ~this.controller.nBitMapMask);
if (this.adw[idw] != dw) {
this.adw[idw] = dw;
@ -1723,19 +1737,6 @@ Card.ACCESS.writeByteMode0EvenOdd = function writeByteMode0EvenOdd(off, b, addr)
/**
* writeByteMode0Rot(off, b, addr)
*
* Supporting Set/Reset means that for every plane for which Set/Reset is enabled, we must
* replace the corresponding byte in "dw" with a byte of zeros or ones. This is accomplished with
* nSetMapMask, nSetMapData, and nSetMapBits. nSetMapMask is the inverse of the ESRESET bits,
* because we use it to mask the processor data; nSetMapData records the desired SRESET bits; and
* nSetMapBits contains the bits to replace those that we masked in the processor data.
*
* We could have done this:
*
* dw = (dw & this.controller.nSetMapMask) | (this.controller.nSetMapData & ~this.controller.nSetMapMask)
*
* but by maintaining nSetMapBits equal to (nSetMapData & ~nSetMapMask), we are able to make the writes
* slightly more efficient.
*
* @this {Memory}
* @param {number} off
* @param {number} b (which should already be pre-masked to 8 bits; see Bus.prototype.setByteDirect)
@ -5062,7 +5063,11 @@ Video.prototype.getRetraceBits = function(card)
*/
var nCycles = this.cpu.getCycles();
var nElapsedCycles = nCycles - card.nInitCycles;
if (nElapsedCycles < 0) nElapsedCycles = 0; // TODO: Determine if this ever happens
if (nElapsedCycles < 0) {
this.assert(nCycles === 0);
card.nInitCycles = nElapsedCycles;
nElapsedCycles = -nElapsedCycles|0;
}
var nCyclesHorzRemain = nElapsedCycles % card.nCyclesHorzPeriod;
if (nCyclesHorzRemain > card.nCyclesHorzActive) b |= Card.CGA.STATUS.DISP_RETRACE;
var nCyclesVertRemain = nElapsedCycles % card.nCyclesVertPeriod;
@ -5076,7 +5081,7 @@ Video.prototype.getRetraceBits = function(card)
*
* NOTE: Now that we're calling getRetraceBits() more frequently (ie, for internal checks), resetting nInitCycles
* in this fashion preserves the vertical period at the expense of the horizontal period, which in turn can cause
* grief in ROM BIOS code that requires strict horizontal retrace times. So the above code is now disabled.
* grief in ROM BIOS code that requires strict horizontal retrace times. TODO: Figure out how to re-enable this code.
*/
return b;
};