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Added placeholders for IBTS and XBTS (80386 opcodes on A0-B0 steppings only)

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This commit is contained in:
Jeff Parsons 2015-10-29 22:44:33 -07:00
commit 8bd1794928
7 changed files with 139 additions and 75 deletions
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52
modules/pcjs/lib/x86func.js
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@ -683,6 +683,28 @@ X86.fnDECw = function(dst, src)
return w & this.maskData;
};
/**
* fnIBTS(dst, src)
*
* As best I can determine, this function copies the specified bits from src (starting at bit 0 for CL
* bits) to dst (starting at bit offset in AX). For register operands, that's simple enough.
*
* TODO: If dst refers to a memory location, then the bit index may refer to higher memory locations, just
* like the BT/BTC/BTR/BTS instructions. For an instruction that no one was really able to use, except
* as a CPU stepping discriminator, that doesn't seem worth the effort.
*
* @this {X86CPU}
* @param {number} dst
* @param {number} src
* @return {number}
*/
X86.fnIBTS = function(dst, src)
{
var shift = (this.regEAX & this.maskData);
var mask = ((1 << (this.regECX & 0x1f)) - 1);
return (dst & ~(mask << shift)) | ((src & mask) << shift);
};
/**
* fnSet64(lo, hi)
*
@ -2033,11 +2055,11 @@ X86.fnMULw = function(dst, src)
this.regMDHi = (result >> 16) & 0xffff;
} else {
X86.fnMUL32.call(this, dst, this.regEAX);
if (this.model == X86.MODEL_80386 && this.stepping == X86.STEPPING_B1) {
if (this.stepping == X86.STEPPING_80386_B1) {
if (this.regEAX == 0x0417A000 && dst == 0x00000081) {
/*
* In this case, the result should be 0x20FE7A000 (ie, regMDHi should be 0x2), and I'm not
* sure what the typical failure would look like, so I'll just set regMDHi to 0.
* Normally, the result should be 0x20FE7A000 (ie, regMDHi should be 0x2).
* I'm not sure what a typical failure looked like, so I'll just set regMDHi to 0.
*
* If you want a B1 stepping without this 32-bit multiplication flaw, select the B2 stepping.
*/
@ -3538,6 +3560,30 @@ X86.fnVERW = function(dst, src)
return dst;
};
/**
* fnXBTS(dst, src)
*
* As best I can determine, this function copies the specified bits from src (starting at the bit offset
* in AX, for the bit length in CL) to dst (starting at bit 0). For register operands, that's simple enough.
*
* TODO: If src refers to a memory location, then the bit index may refer to higher memory locations, just
* like the BT/BTC/BTR/BTS instructions. For an instruction that no one was really able to use, except
* as a CPU stepping discriminator, that doesn't seem worth the effort.
*
* @this {X86CPU}
* @param {number} dst
* @param {number} src
* @return {number}
*/
X86.fnXBTS = function(dst, src)
{
/*
* Shift src right by the bit offset in [E]AX, then apply a mask equal to the number of bits in CL,
* then mask the resulting bit string with the current OPERAND size.
*/
return ((src >> (this.regEAX & this.maskData)) & ((1 << (this.regECX & 0x1f)) - 1)) & this.maskData;
};
/**
* fnXCHGrb(dst, src)
*