diff options
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/x86/isa/microops/regop.isa | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/src/arch/x86/isa/microops/regop.isa b/src/arch/x86/isa/microops/regop.isa index 7ce9dc27f..d2cfff9d4 100644 --- a/src/arch/x86/isa/microops/regop.isa +++ b/src/arch/x86/isa/microops/regop.isa @@ -460,6 +460,11 @@ let {{ class Xor(LogicRegOp): code = 'DestReg = merge(DestReg, psrc1 ^ op2, dataSize)' + # Neither of these is quite correct because it assumes that right shifting + # a signed or unsigned value does sign or zero extension respectively. + # The C standard says that what happens on a right shift with a 1 in the + # MSB position is undefined. On x86 and under likely most compilers the + # "right thing" happens, but this isn't a guarantee. class Mul1s(WrRegOp): code = ''' ProdLow = psrc1 * op2; @@ -489,11 +494,6 @@ let {{ class Mulel(RdRegOp): code = 'DestReg = merge(SrcReg1, ProdLow, dataSize);' - # Neither of these is quite correct because it assumes that right shifting - # a signed or unsigned value does sign or zero extension respectively. - # The C standard says that what happens on a right shift with a 1 in the - # MSB position is undefined. On x86 and under likely most compilers the - # "right thing" happens, but this isn't a guarantee. class Muleh(RdRegOp): def __init__(self, dest, src1=None, flags=None, dataSize="env.dataSize"): if not src1: |