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JIT: a small optimization for subfex and friends

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This commit is contained in:
Fiora 2014-09-21 12:16:26 -07:00
parent 9f2d4ee53e
commit 505b1bd562
1 changed files with 13 additions and 3 deletions
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14
Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp
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@ -1307,14 +1307,24 @@ void Jit64::arithXex(UGeckoInstruction inst)
else
{
OpArg source = regsource ? gpr.R(d == b ? a : b) : Imm32(mex ? 0xFFFFFFFF : 0);
if (js.carryFlagInverted)
CMC();
if (d != a && d != b)
MOV(32, gpr.R(d), gpr.R(a));
if (!add)
NOT(32, gpr.R(d));
// if the source is an immediate, we can invert carry by going from add -> sub and doing src = -1 - src
if (js.carryFlagInverted && source.IsImm())
{
source.offset = -1 - (s32)source.offset;
SBB(32, gpr.R(d), source);
invertedCarry = true;
}
else
{
if (js.carryFlagInverted)
CMC();
ADC(32, gpr.R(d), source);
}
}
FinalizeCarryOverflow(inst.OE, invertedCarry);
if (inst.Rc)
ComputeRC(gpr.R(d));