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OpcodeDispatcher: optimize RDRAND on flagm

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Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
This commit is contained in:
Alyssa Rosenzweig 2024-08-10 15:17:10 -04:00
parent d9c779289c
commit 91f4c54768
1 changed files with 11 additions and 3 deletions
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14
FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
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@ -4925,12 +4925,20 @@ void OpDispatchBuilder::RDRANDOp(OpcodeArgs) {
StoreResult(GPRClass, Op, _RDRAND(Reseed), -1);
// If the rng number is valid then NZCV is 0b0000, otherwise NZCV is 0b0100
auto Invalid = GetRFLAG(X86State::RFLAG_ZF_RAW_LOC);
auto CF_inv = GetRFLAG(X86State::RFLAG_ZF_RAW_LOC);
// OF, SF, ZF, AF, PF all zero. CF indicates if valid.
ZeroNZCV();
ZeroPF_AF();
SetCFInverted(Invalid);
if (!CTX->HostFeatures.SupportsFlagM) {
ZeroNZCV();
SetCFInverted(CF_inv);
} else {
// Accelerated path. Invalid is 0 or 1, so set NZCV with a single rmif.
HandleNZCVWrite(1u << 29 /* C */);
_RmifNZCV(CF_inv, (64 - 1) /* rotate bit 0 into bit 1 = C */, 0xf);
CFInverted = true;
}
}
void OpDispatchBuilder::BreakOp(OpcodeArgs, FEXCore::IR::BreakDefinition BreakDefinition) {