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Force all segment register writes to be 16-bit, even when the operand size is 32-bit

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This commit is contained in:
Jeff Parsons 2016-01-27 10:58:01 -08:00
commit adb2b9aa90
9 changed files with 1265 additions and 1216 deletions
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24
modules/pcjs/lib/x86op0f.js
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@ -1109,11 +1109,15 @@ X86.opSETNLE = function()
X86.opPUSHFS = function()
{
/*
* TODO: Reportedly, when the OPERAND size is 32 bits, the 80386 will decrement the stack pointer by 4,
* write the selector into the 2 lower bytes, and leave the 2 upper bytes untouched, whereas we will write
* a 32-bit value, effectively zeroing the 2 upper bytes. Need to confirm this.
* When the OPERAND size is 32 bits, the 80386 will decrement the stack pointer by 4, write the selector
* into the 2 lower bytes, and leave the 2 upper bytes untouched; to properly emulate that, we must use the
* more generic pushData() instead of pushWord().
*/
this.pushWord(this.segFS.sel);
if (!I386) {
this.pushWord(this.segFS.sel);
} else {
this.pushData(this.segFS.sel, this.sizeData, 2);
}
this.nStepCycles -= this.cycleCounts.nOpCyclesPushSeg;
};
@ -1210,11 +1214,15 @@ X86.opIBTS = function()
X86.opPUSHGS = function()
{
/*
* TODO: Reportedly, when the OPERAND size is 32 bits, the 80386 will decrement the stack pointer by 4,
* write the selector into the 2 lower bytes, and leave the 2 upper bytes untouched, whereas we will write
* a 32-bit value, effectively zeroing the 2 upper bytes. Need to confirm this.
* When the OPERAND size is 32 bits, the 80386 will decrement the stack pointer by 4, write the selector
* into the 2 lower bytes, and leave the 2 upper bytes untouched; to properly emulate that, we must use the
* more generic pushData() instead of pushWord().
*/
this.pushWord(this.segGS.sel);
if (!I386) {
this.pushWord(this.segGS.sel);
} else {
this.pushData(this.segGS.sel, this.sizeData, 2);
}
this.nStepCycles -= this.cycleCounts.nOpCyclesPushSeg;
};