Flag Optimizations #222
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Flag Optimizations #222
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- Nets about 5% Performance Increase locally
paladine
reviewed
Oct 28, 2020
paladine
approved these changes
Oct 28, 2020
paladine
approved these changes
Oct 30, 2020
MBBSEmu/CPU/CPUCore.cs
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| { | ||
| Registers.F = Registers.F.ClearFlag((ushort)EnumFlags.ZF); | ||
| } | ||
| Registers.F = result.IsNegative() ? Registers.F.SetFlag((ushort)EnumFlags.SF) : Registers.F.ClearFlag((ushort)EnumFlags.SF); |
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if result.IsNegative() you can skip evaluation of Zero since it's obviously not 0
e.g.
if (result.IsNegative()) {
setFlag(SF);
clearFlag(ZF);
} else {
clearFlag(SF);
if (result == 0) .... set | clear
}
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Nets about a 5% speed bump in the benchmark on my local machine.