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X86: Implement a microop that compares fp values and writes to rflags.

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This commit is contained in:
Gabe Black 2009-08-17 20:25:14 -07:00
parent 7d4db7266e
commit 2c9ee52c37
1 changed files with 55 additions and 0 deletions
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55
src/arch/x86/isa/microops/mediaop.isa
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@ -1342,4 +1342,59 @@ let {{
}
FpDestReg.uqw = result;
'''
class Mcmpf2rf(MediaOp):
def __init__(self, src1, src2,\
size = None, destSize = None, srcSize = None, ext = None):
super(Mcmpf2rf, self).__init__("InstRegIndex(0)", src1,\
src2, size, destSize, srcSize, ext)
code = '''
union floatInt
{
float f;
uint32_t i;
};
union doubleInt
{
double d;
uint64_t i;
};
assert(srcSize == destSize);
assert(srcSize == 4 || srcSize == 8);
int size = srcSize;
int sizeBits = size * 8;
double arg1, arg2;
uint64_t arg1Bits = bits(FpSrcReg1.uqw, sizeBits - 1, 0);
uint64_t arg2Bits = bits(FpSrcReg2.uqw, sizeBits - 1, 0);
if (size == 4) {
floatInt fi;
fi.i = arg1Bits;
arg1 = fi.f;
fi.i = arg2Bits;
arg2 = fi.f;
} else {
doubleInt di;
di.i = arg1Bits;
arg1 = di.d;
di.i = arg2Bits;
arg2 = di.d;
}
// ZF PF CF
// Unordered 1 1 1
// Greater than 0 0 0
// Less than 0 0 1
// Equal 1 0 0
// OF = SF = AF = 0
ccFlagBits = ccFlagBits & ~(OFBit | SFBit | AFBit |
ZFBit | PFBit | CFBit);
if (isnan(arg1) || isnan(arg2))
ccFlagBits = ccFlagBits | (ZFBit | PFBit | CFBit);
else if(arg1 < arg2)
ccFlagBits = ccFlagBits | CFBit;
else if(arg1 == arg2)
ccFlagBits = ccFlagBits | ZFBit;
'''
}};