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SRC operands must be fetched before DST operands (continued)

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Jeff 2016-10-03 16:57:15 -07:00 • committed by Jeff Parsons
commit fc48982d4c
1 changed files with 8 additions and 4 deletions
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12
modules/pdp11/lib/cpuops.js
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@ -701,7 +701,7 @@ PDP11.opBISB = function(opCode)
PDP11.opBIT = function(opCode) PDP11.opBIT = function(opCode)
{ {
/* /*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode, * NOTE: Because readWordByMode() will be used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before they get overwritten. * the srcMode and srcReg properties need to be copied before they get overwritten.
*/ */
var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT); var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT);
@ -725,7 +725,7 @@ PDP11.opBIT = function(opCode)
PDP11.opBITB = function(opCode) PDP11.opBITB = function(opCode)
{ {
/* /*
* NOTE: Because readByteByMode() is being used to READ (not WRITE) the DSTMODE field of opCode, * NOTE: Because readByteByMode() will be used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before they get overwritten. * the srcMode and srcReg properties need to be copied before they get overwritten.
*/ */
var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT); var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT);
@ -994,7 +994,7 @@ PDP11.opCLx = function(opCode)
PDP11.opCMP = function(opCode) PDP11.opCMP = function(opCode)
{ {
/* /*
* NOTE: Because readWordByMode() is being used to READ (not WRITE) the DSTMODE field of opCode, * NOTE: Because readWordByMode() will be used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before they get overwritten. * the srcMode and srcReg properties need to be copied before they get overwritten.
*/ */
var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT); var src = this.readWordByMode(opCode >> PDP11.SRCMODE.SHIFT);
@ -1023,7 +1023,7 @@ PDP11.opCMP = function(opCode)
PDP11.opCMPB = function(opCode) PDP11.opCMPB = function(opCode)
{ {
/* /*
* NOTE: Because readByteByMode() is being used to READ (not WRITE) the DSTMODE field of opCode, * NOTE: Because readByteByMode() will be used to READ (not WRITE) the DSTMODE field of opCode,
* the srcMode and srcReg properties need to be copied before they get overwritten. * the srcMode and srcReg properties need to be copied before they get overwritten.
*/ */
var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) << 8; var src = this.readByteByMode(opCode >> PDP11.SRCMODE.SHIFT) << 8;
@ -1237,6 +1237,10 @@ PDP11.opJSR = function(opCode)
* srcMode rather than dstMode, because JSR does not WRITE the dst operand; it merely READs it. * srcMode rather than dstMode, because JSR does not WRITE the dst operand; it merely READs it.
*/ */
var nSnapCycles = this.nStepCycles; var nSnapCycles = this.nStepCycles;
/*
* TODO: Determine whether or not the SRCMODE operand (regsGen[reg]) should be snapped BEFORE or AFTER we
* decode the DSTMODE operand. Doing it AFTER seems a bit risky.
*/
var addr = this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT); var addr = this.getVirtualByMode(opCode, PDP11.ACCESS.VIRT);
var reg = (opCode >> PDP11.SRCMODE.SHIFT) & PDP11.OPREG.MASK; var reg = (opCode >> PDP11.SRCMODE.SHIFT) & PDP11.OPREG.MASK;
this.pushWord(this.regsGen[reg]); this.pushWord(this.regsGen[reg]);