Method CMPXCHGPairOp

FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp:3858–3903

}

void OpDispatchBuilder::CMPXCHGPairOp(OpcodeArgs) {
  // Calculate flags early.
  CalculateDeferredFlags();

  // REX.W used to determine if it is 16byte or 8byte
  // Unlike CMPXCHG, the destination can only be a memory location
  const auto Size = Op->Flags & FEXCore::X86Tables::DecodeFlags::FLAG_REX_WIDENING ? OpSize::i64Bit : OpSize::i32Bit;

  HandledLock = (Op->Flags & FEXCore::X86Tables::DecodeFlags::FLAG_LOCK) != 0;

  // If this is a memory location then we want the pointer to it
  Ref Src1 = MakeSegmentAddress(Op, Op->Dest);

  // Load the full 64-bit registers, all the users ignore the upper 32-bits for
  // 32-bit only cmpxchg. This saves some zero extension.
  Ref Expected_Lower = LoadGPRRegister(X86State::REG_RAX);
  Ref Expected_Upper = LoadGPRRegister(X86State::REG_RDX);
  Ref Desired_Lower = LoadGPRRegister(X86State::REG_RBX);
  Ref Desired_Upper = LoadGPRRegister(X86State::REG_RCX);

  // ssa0 = Expected
  // ssa1 = Desired
  // ssa2 = MemoryLocation

  // DataSrc = *MemSrc
  // if (DataSrc == Expected) { *MemSrc == Desired; } Expected = DataSrc
  // This will write to memory! Careful!
  // Third operand must be a calculated guest memory address

  Ref Result_Lower = _AllocateGPR(true);
  Ref Result_Upper = _AllocateGPRAfter(Result_Lower);
  _CASPair(Size, Expected_Lower, Expected_Upper, Desired_Lower, Desired_Upper, Src1, Result_Lower, Result_Upper);

  HandleNZCV_RMW();
  _CmpPairZ(Size, Result_Lower, Result_Upper, Expected_Lower, Expected_Upper);
  CalculateDeferredFlags();

  auto UpdateIfNotZF = [this](auto Reg, auto Value) {
    // Always use 64-bit csel to preserve existing upper bits. If we have a
    // 32-bit cmpxchg in a 64-bit context, Value will be zeroed in upper bits.
    StoreGPRRegister(Reg, NZCVSelect(OpSize::i64Bit, {COND_NEQ}, Value, LoadGPRRegister(Reg)));
  };

  UpdateIfNotZF(X86State::REG_RAX, Result_Lower);
  UpdateIfNotZF(X86State::REG_RDX, Result_Upper);
}

void OpDispatchBuilder::CreateJumpBlocks(const fextl::vector<FEXCore::Frontend::Decoder::DecodedBlocks>* Blocks) {
  Ref PrevCodeBlock {};