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Fixed "Mode X" read/write access functions (eliminated the CHAIN1 crutch)

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This commit is contained in:
Jeff Parsons 2015-07-07 14:01:53 -07:00
commit 9be10ddc63
1 changed files with 1 additions and 49 deletions
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50
modules/pcjs/lib/video.js
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@ -1592,7 +1592,6 @@ Card.ACCESS = {
MODE1: 0x0500,
EVENODD: 0x1000,
CHAIN4: 0x4000,
CHAIN1: 0x8000,
MASK: 0xFF00
},
WRITE: { // and WRITE values are designed to be OR'ed with READ values
@ -1601,7 +1600,6 @@ Card.ACCESS = {
MODE2: 0x0002,
MODE3: 0x0003, // VGA only
CHAIN4: 0x0004,
CHAIN1: 0x0008,
EVENODD: 0x0010,
ROT: 0x0020,
AND: 0x0060,
@ -1664,24 +1662,6 @@ Card.ACCESS.readByteMode0Chain4 = function readByteMode0Chain4(off, addr)
return ((this.controller.latches = this.adw[idw]) >> shift) & 0xff;
};
/**
* readByteMode0Chain1(off, addr)
*
* TODO: Although this function is used only for 8bpp modes, its operation does not differ from readByteMode0(),
* so if that continues to hold true, we should eliminate this function and map CHAIN1 support to readByteMode0().
*
* @this {Memory}
* @param {number} off
* @param {number} [addr]
* @return {number}
*/
Card.ACCESS.readByteMode0Chain1 = function readByteMode0Chain1(off, addr)
{
off += this.offset;
var dw = this.controller.latches = this.adw[off];
return (dw >> this.controller.nReadMapShift) & 0xff;
};
/**
* readByteMode0EvenOdd(off, addr)
*
@ -1825,29 +1805,6 @@ Card.ACCESS.writeByteMode0Chain4 = function writeByteMode0Chain4(off, b, addr)
}
};
/**
* writeByteMode0Chain1(off, b, addr)
*
* TODO: Although this function is similar to writeByteMode0(), it's used only for 8bpp modes, so it remains to
* be seen how much of the former will need to be folded into this; if it's everything, then we can eliminate this
* function and map CHAIN1 support to writeByteMode0().
*
* @this {Memory}
* @param {number} off
* @param {number} b (which should already be pre-masked to 8 bits; see Bus.prototype.setByteDirect)
* @param {number} [addr]
*/
Card.ACCESS.writeByteMode0Chain1 = function writeByteMode0Chain1(off, b, addr)
{
var idw = off + this.offset;
var dw = b | (b << 8) | (b << 16) | (b << 24);
dw = (dw & this.controller.nSeqMapMask) | (this.adw[idw] & ~this.controller.nSeqMapMask);
if (this.adw[idw] != dw) {
this.adw[idw] = dw;
this.fDirty = true;
}
};
/**
* writeByteMode0EvenOdd(off, b, addr)
*
@ -2129,7 +2086,6 @@ Card.ACCESS.afn = [];
Card.ACCESS.afn[Card.ACCESS.READ.MODE0] = Card.ACCESS.readByteMode0;
Card.ACCESS.afn[Card.ACCESS.READ.MODE0 | Card.ACCESS.READ.CHAIN4] = Card.ACCESS.readByteMode0Chain4;
Card.ACCESS.afn[Card.ACCESS.READ.MODE0 | Card.ACCESS.READ.CHAIN1] = Card.ACCESS.readByteMode0Chain1;
Card.ACCESS.afn[Card.ACCESS.READ.MODE0 | Card.ACCESS.READ.EVENODD] = Card.ACCESS.readByteMode0EvenOdd;
Card.ACCESS.afn[Card.ACCESS.READ.MODE1] = Card.ACCESS.readByteMode1;
@ -2139,7 +2095,6 @@ Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.AND] = Card.ACCESS.
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.OR] = Card.ACCESS.writeByteMode0Or;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.XOR] = Card.ACCESS.writeByteMode0Xor;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.CHAIN4] = Card.ACCESS.writeByteMode0Chain4;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.CHAIN1] = Card.ACCESS.writeByteMode0Chain1;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE0 | Card.ACCESS.WRITE.EVENODD] = Card.ACCESS.writeByteMode0EvenOdd;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE1] = Card.ACCESS.writeByteMode1;
Card.ACCESS.afn[Card.ACCESS.WRITE.MODE1 | Card.ACCESS.WRITE.EVENODD] = Card.ACCESS.writeByteMode1EvenOdd;
@ -4229,9 +4184,6 @@ Video.prototype.getAccess = function()
if (regSEQMode & Card.SEQ.MEMMODE.CHAIN4) {
nReadAccess |= Card.ACCESS.READ.CHAIN4;
nWriteAccess |= Card.ACCESS.WRITE.CHAIN4;
} else {
nReadAccess |= Card.ACCESS.READ.CHAIN1;
nWriteAccess |= Card.ACCESS.WRITE.CHAIN1;
}
this.fColor256 = true;
}
@ -5340,7 +5292,7 @@ Video.prototype.updateScreenGraphicsEGA = function(addrScreen, addrScreenLimit)
* (first introduced by the EGA and later expanded by the VGA), where each pixel's bits are spread across the 4
* planes, whereas this function takes care of just the 8bpp video modes introduced by the VGA, such as mode 0x13
* (320x200x256), where each pixel's bits are contained within a single plane. This is essentially all 256-color
* (CHAIN4, CHAIN1, etc) modes, hence the hard-coded call to getCardColors(8).
* modes (CHAIN4, "Mode X", etc), hence the hard-coded call to getCardColors(8).
*
* @param addrScreen
* @param addrScreenLimit