Method DECOp

FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp:3144–3183

}

void OpDispatchBuilder::DECOp(OpcodeArgs) {
  Ref Dest;
  Ref Result;
  const auto Size = GetSrcBitSize(Op);
  const bool IsLocked = DestIsLockedMem(Op);

  if (IsLocked) {
    HandledLock = true;

    Ref DestAddress = MakeSegmentAddress(Op, Op->Dest);

    // Use Add instead of Sub to avoid a NEG
    Dest = _AtomicFetchAdd(OpSizeFromSrc(Op), Constant(Size == 64 ? -1 : ((1ULL << Size) - 1)), DestAddress);
  } else {
    Dest = LoadSource(GPRClass, Op, Op->Dest, Op->Flags, {.AllowUpperGarbage = Size >= 32});
  }

  CalculateDeferredFlags();

  if (Size < 32 && CTX->HostFeatures.SupportsFlagM) {
    // Subtraction producing upper garbage
    Result = Sub(OpSize::i32Bit, Dest, 1);
    CalculatePF(Result);
    CalculateAF(Dest, Constant(1));

    // Correctly set NZ flags, preserving C
    HandleNZCV_RMW();
    _SetSmallNZV(OpSizeFromSrc(Op), Result);

    // Fix up V flag. DEC overflows only when decrementing a negative and
    // getting a positive. So compare the sign bits to calculate V.
    _RmifNZCV(_Andn(OpSize::i32Bit, Dest, Result), Size - 1, 1);
  } else {
    Result = CalculateFlags_SUB(OpSizeFromSrc(Op), Dest, Constant(1), false);
  }

  if (!IsLocked) {
    StoreResult(GPRClass, Op, Result, OpSize::iInvalid);
  }
}

void OpDispatchBuilder::STOSOp(OpcodeArgs) {
  if (Op->Flags & FEXCore::X86Tables::DecodeFlags::FLAG_ADDRESS_SIZE) {