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OpcodeDispatcher: optimize RCL

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Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
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Alyssa Rosenzweig committed 2023-11-13 21:21:01 -04:00
1 parent c9f13ae1dd
commit 651b7bb75d
1 file changed
+45 -41
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FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+45 -41
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@@ -2633,64 +2633,68 @@ void OpDispatchBuilder::RCLOp(OpcodeArgs) {
RCLSmallerOp(Op);
return;
}
const auto OpSize = OpSizeFromSrc(Op);
// Calculate flags early.
CalculateDeferredFlags();
OrderedNode *Src = LoadSource(GPRClass, Op, Op->Src[1], Op->Flags);
OrderedNode *Dest = LoadSource(GPRClass, Op, Op->Dest, Op->Flags);
auto CF = GetRFLAG(FEXCore::X86State::RFLAG_CF_RAW_LOC);
// Res = Src << Shift
OrderedNode *Res = _Lshl(OpSize, Dest, Src);
CalculateFlags_ShiftVariable(Src, [this, CF, Op, Size, Src](){
// Res = Src << Shift
const auto OpSize = OpSizeFromSrc(Op);
OrderedNode *Dest = LoadSource(GPRClass, Op, Op->Dest, Op->Flags);
OrderedNode *Res = _Lshl(OpSize, Dest, Src);
// Res |= (Src << (Size - Shift + 1));
OrderedNode *SrcShl = _Sub(OpSize, _Constant(Size, Size + 1), Src);
auto TmpHigher = _Lshr(OpSize, Dest, SrcShl);
uint64_t Const;
if (!IsValueConstant(WrapNode(Src), &Const)) {
// Res |= (Src << (Size - Shift + 1));
OrderedNode *SrcShl = _Sub(OpSize, _Constant(Size, Size + 1), Src);
auto TmpHigher = _Lshr(OpSize, Dest, SrcShl);
auto One = _Constant(Size, 1);
auto Zero = _Constant(Size, 0);
auto One = _Constant(Size, 1);
auto Zero = _Constant(Size, 0);
auto CompareResult = _Select(FEXCore::IR::COND_UGT,
Src, One,
TmpHigher, Zero);
auto CompareResult = _Select(FEXCore::IR::COND_UGT, Src, One, TmpHigher, Zero);
Res = _Or(OpSize, Res, CompareResult);
Res = _Or(OpSize, Res, CompareResult);
// Our new CF will be bit (Shift - 1) of the source
auto NewCF = _Lshr(OpSize, Dest, _Sub(OpSize, _Constant(Size, Size), Src));
SetRFLAG<FEXCore::X86State::RFLAG_CF_RAW_LOC>(NewCF, 0, true);
// If Shift != 0 then we can inject the CF
OrderedNode *CFShl = _Sub(OpSize, Src, _Constant(Size, 1));
auto TmpCF = _Lshl(OpSize::i64Bit, CF, CFShl);
// Since Shift != 0 we can inject the CF
OrderedNode *CFShl = _Sub(OpSize, Src, _Constant(Size, 1));
auto TmpCF = _Lshl(OpSize::i64Bit, CF, CFShl);
Res = _Or(OpSize, Res, TmpCF);
CompareResult = _Select(FEXCore::IR::COND_UGE,
Src, One,
TmpCF, Zero);
// OF is the top two MSBs XOR'd together
// Only when Shift == 1, it is undefined otherwise
//
// Note that NewCF has garbage in the upper bits, but we ignore them here
// and mask as part of the set after.
auto NewOF = _XorShift(OpSize, Res, NewCF, ShiftType::LSL, Size - 1);
SetRFLAG<FEXCore::X86State::RFLAG_OF_RAW_LOC>(NewOF, Size - 1, true);
} else {
// Res |= (Src << (Size - Shift + 1));
if (Const > 1)
Res = _Orlshr(OpSize, Res, Dest, Size + 1 - Const);
Res = _Or(OpSize, Res, CompareResult);
// Our new CF will be bit (Shift - 1) of the source
SetRFLAG<FEXCore::X86State::RFLAG_CF_RAW_LOC>(Dest, Size - Const, true);
StoreResult(GPRClass, Op, Res, -1);
// Since Shift != 0 we can inject the CF
Res = _Orlshl(OpSize, Res, CF, Const - 1);
{
// CF only changes if we actually shifted
// Our new CF will be bit (Shift - 1) of the source
auto NewCF = _Bfe(OpSize, 1, 0, _Lshr(OpSize, Dest, _Sub(OpSize, _Constant(Size, Size), Src)));
CompareResult = _Select(FEXCore::IR::COND_UGE,
Src, One,
NewCF, CF);
// OF is the top two MSBs XOR'd together
// Only when Shift == 1, it is undefined otherwise
if (Const == 1) {
auto NewOF = _Xor(OpSize, Res, Dest);
SetRFLAG<FEXCore::X86State::RFLAG_OF_RAW_LOC>(NewOF, Size - 1, true);
}
}
SetRFLAG<FEXCore::X86State::RFLAG_CF_RAW_LOC>(CompareResult);
// OF is the top two MSBs XOR'd together
// Only when Shift == 1, it is undefined otherwise
// Only changed if shift isn't zero
auto OF = GetRFLAG(FEXCore::X86State::RFLAG_OF_RAW_LOC);
auto NewOF = _Xor(OpSize, _Bfe(OpSize, 1, Size - 1, Res), NewCF);
CompareResult = _Select(FEXCore::IR::COND_EQ,
Src, _Constant(0),
OF, NewOF);
SetRFLAG<FEXCore::X86State::RFLAG_OF_RAW_LOC>(CompareResult);
}
StoreResult(GPRClass, Op, Res, -1);
});
}
void OpDispatchBuilder::RCLSmallerOp(OpcodeArgs) {