changeset 57e6d35dde10 in /z/repo/m5
details: http://repo.m5sim.org/m5?cmd=changeset;node=57e6d35dde10
description:
X86: Handle rotate left with carry instructions that go all the way
around or more.
diffstat:
1 file changed, 9 insertions(+), 6 deletions(-)
src/arch/x86/isa/microops/regop.isa | 15 +++++++++------
diffs (42 lines):
diff -r 709527fb7250 -r 57e6d35dde10 src/arch/x86/isa/microops/regop.isa
--- a/src/arch/x86/isa/microops/regop.isa Wed Aug 05 03:02:05 2009 -0700
+++ b/src/arch/x86/isa/microops/regop.isa Wed Aug 05 03:02:28 2009 -0700
@@ -839,15 +839,16 @@
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 @@
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))
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