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| author | Gabe Black <gblack@eecs.umich.edu> | 2009-08-05 03:02:28 -0700 |
|---|---|---|
| committer | Gabe Black <gblack@eecs.umich.edu> | 2009-08-05 03:02:28 -0700 |
| commit | c4140d7d6038a3b44dfd04065e02666975cfa651 (patch) | |
| tree | 71fe01c43a8a56073143122bed2b8cf160d407f1 /src/arch/x86/isa/microops | |
| parent | 3990445354914ffc3a56ceb93b1fde222d7236c6 (diff) | |
| download | gem5-c4140d7d6038a3b44dfd04065e02666975cfa651.tar.xz | |
X86: Handle rotate left with carry instructions that go all the way around or more.
Diffstat (limited to 'src/arch/x86/isa/microops')
| -rw-r--r-- | src/arch/x86/isa/microops/regop.isa | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/arch/x86/isa/microops/regop.isa b/src/arch/x86/isa/microops/regop.isa index 477034224..e0228ec0e 100644 --- a/src/arch/x86/isa/microops/regop.isa +++ b/src/arch/x86/isa/microops/regop.isa @@ -839,15 +839,16 @@ let {{ code = ''' uint8_t shiftAmt = (op2 & ((dataSize == 8) ? mask(6) : mask(5))); - if(shiftAmt) + uint8_t realShiftAmt = shiftAmt % (dataSize * 8 + 1); + if(realShiftAmt) { CCFlagBits flags = ccFlagBits; - uint64_t top = psrc1 << shiftAmt; - uint64_t bottom = flags.cf << (shiftAmt - 1); + uint64_t top = psrc1 << realShiftAmt; + uint64_t bottom = flags.cf << (realShiftAmt - 1); if(shiftAmt > 1) bottom |= bits(psrc1, dataSize * 8 - 1, - dataSize * 8 - shiftAmt + 1); + dataSize * 8 - realShiftAmt + 1); DestReg = merge(DestReg, top | bottom, dataSize); } else @@ -856,13 +857,15 @@ let {{ flag_code = ''' // If the shift amount is zero, no flags should be modified. if (shiftAmt) { + int origCFBit = (ccFlagBits & CFBit) ? 1 : 0; //Zero out any flags we might modify. This way we only have to //worry about setting them. ccFlagBits = ccFlagBits & ~(ext & (CFBit | ECFBit | OFBit)); int msb = bits(DestReg, dataSize * 8 - 1); - int CFBits = bits(SrcReg1, dataSize * 8 - shiftAmt); + int CFBits = bits(SrcReg1, dataSize * 8 - realShiftAmt); //If some combination of the CF bits need to be set, set them. - if ((ext & (CFBit | ECFBit)) && CFBits) + if ((ext & (CFBit | ECFBit)) && + (realShiftAmt == 0) ? origCFBit : CFBits) ccFlagBits = ccFlagBits | (ext & (CFBit | ECFBit)); //Figure out what the OF bit should be. if ((ext & OFBit) && (msb ^ CFBits)) |