Method BTOp

FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp:2389–2541

}

void OpDispatchBuilder::BTOp(OpcodeArgs, uint32_t SrcIndex, BTAction Action) {
  Ref Value;
  ArithRef Src;
  bool IsNonconstant = Op->Src[SrcIndex].IsGPR();

  const uint32_t Size = GetDstBitSize(Op);
  const uint32_t Mask = Size - 1;

  if (IsNonconstant) {
    // Because we mask explicitly with And/Bfe/Sbfe after, we can allow garbage here.
    Src = ARef(LoadSource(GPRClass, Op, Op->Src[SrcIndex], Op->Flags, {.AllowUpperGarbage = true}));
  } else {
    // Can only be an immediate
    // Masked by operand size
    Src = ARef(Op->Src[SrcIndex].Data.Literal.Value & Mask);
  }

  if (Op->Dest.IsGPR()) {
    // When the destination is a GPR, we don't care about garbage in the upper bits.
    // Load the full register.
    auto Dest = LoadSource_WithOpSize(GPRClass, Op, Op->Dest, GetGPROpSize(), Op->Flags);
    Value = Dest;

    // Get the bit selection from the src. We need to mask for 8/16-bit, but
    // rely on the implicit masking of Lshr for native sizes.
    unsigned LshrSize = std::max<uint8_t>(IR::OpSizeToSize(OpSize::i32Bit), Size / 8);
    auto BitSelect = (Size == (LshrSize * 8)) ? Src : Src.And(Mask);
    auto LshrOpSize = IR::SizeToOpSize(LshrSize);

    // OF/SF/AF/PF undefined. ZF must be preserved. We choose to preserve OF/SF
    // too since we just use an rmif to insert into CF directly. We could
    // optimize perhaps.
    //
    // Set CF before the action to save a move, except for complements where we
    // can reuse the invert.
    if (Action != BTAction::BTComplement) {
      if (IsNonconstant) {
        Value = _Lshr(IR::SizeToOpSize(LshrSize), Value, BitSelect.Ref());
      }

      SetRFLAG(Value, X86State::RFLAG_CF_RAW_LOC, Src.IsConstant ? Src.C : 0, true);
      CFInverted = false;
    }

    switch (Action) {
    case BTAction::BTNone: {
      /* Nothing to do */
      break;
    }

    case BTAction::BTClear: {
      Dest = _Andn(LshrOpSize, Dest, BitSelect.MaskBit(LshrOpSize).Ref());
      StoreResult(GPRClass, Op, Dest, OpSize::iInvalid);
      break;
    }

    case BTAction::BTSet: {
      Dest = _Or(LshrOpSize, Dest, BitSelect.MaskBit(LshrOpSize).Ref());