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X86: Fix the overflow bit for rotate right with carry.

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This commit is contained in:
Gabe Black 2009-08-05 03:01:23 -07:00
parent c8b1a4583e
commit 77dc6b33ee
1 changed files with 4 additions and 2 deletions
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6
src/arch/x86/isa/microops/regop.isa
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@ -777,13 +777,15 @@ let {{
flag_code = ''' flag_code = '''
// If the shift amount is zero, no flags should be modified. // If the shift amount is zero, no flags should be modified.
if (shiftAmt) { if (shiftAmt) {
int origCFBit = (ccFlagBits & CFBit) ? 1 : 0;
//Zero out any flags we might modify. This way we only have to //Zero out any flags we might modify. This way we only have to
//worry about setting them. //worry about setting them.
ccFlagBits = ccFlagBits & ~(ext & (CFBit | ECFBit | OFBit)); ccFlagBits = ccFlagBits & ~(ext & (CFBit | ECFBit | OFBit));
//Figure out what the OF bit should be. //Figure out what the OF bit should be.
if ((ext & OFBit) && ((ccFlagBits & CFBit) ^ if ((ext & OFBit) && (origCFBit ^
bits(SrcReg1, dataSize * 8 - 1))) bits(SrcReg1, dataSize * 8 - 1))) {
ccFlagBits = ccFlagBits | OFBit; ccFlagBits = ccFlagBits | OFBit;
}
//If some combination of the CF bits need to be set, set them. //If some combination of the CF bits need to be set, set them.
if ((ext & (CFBit | ECFBit)) && bits(SrcReg1, shiftAmt - 1)) if ((ext & (CFBit | ECFBit)) && bits(SrcReg1, shiftAmt - 1))
ccFlagBits = ccFlagBits | (ext & (CFBit | ECFBit)); ccFlagBits = ccFlagBits | (ext & (CFBit | ECFBit));