Generating Assembler Instruction Opcodes

Assembler instructions (in fact mnemonics) are stored in a symbol table where each instruction has few data bytes which define which procedure will process it and what combinations of parameters are possible.

Type PInstructionData = ^TInstructionData;
     TInstructionData = Record
                          B0,       { x654321x  = InstructionProc shl 1 }

                          B1: Byte; { 76xx xxxx = Number of parameters
                                    { xxxx x2xx = Instruction 80286 }
                                    { xxxx xx10 = Number of additinal data bytes - 1 }

                          Data: Array [0..7] of Byte;
                        end;

This procedure iterates over all possible parameter combinations for current instruction and if right combination of parameters is found, the associated procedure is called.

Procedure GenerateInstructionOpcodes;
begin
  Repeat
    SizeOfAsmIntermediateCodeRecords := 0;
    LastOpCodeBeforeDataValid := False;
    Direction := 0;
    SegmentOverrideOpCode := 0;
    If InstructionData^.B1 shr 6 = ExpressionCounter then
      begin
        LeftExpression  := @AsmExpression1;
        RightExpression := @AsmExpression2;
        LeftToken := LeftExpression^.Token;
        RightToken := RightExpression^.Token;
        InstructionProcessed := False;
        InstructionProc [(InstructionData^.B0 and $7E) shr 1];
        If InstructionProcessed then Break;
      end;
    If InstructionData^.B0 and $80 = 0 then                 { Last variant }
      begin
        If ExpressionCounter < 2 then
          AsmSourceErrorPosition := ErrorPositionInstructionExpresion1 else
            AsmSourceErrorPosition := ErrorPositionInstructionExpresion2;
        AsmError (InvalidCombinationOfOpcodeAndOperands);
      end;
    Inc (PChar (InstructionData), NumberOfOpCodesBeforeModem + 2);
  until False;
  If (InstructionData^.B1 and $04 <> 0) and (Flags and $03 = 0) then
    begin
      AsmSourceErrorPosition := ErrorPositionInstructionExpresion1;
      AsmError (_286_287_InstructionsAreNotEnabled);
    end;
  GenerateLastOpCodeBeforeData;
<span>end;</span>

This table contains opcode generation procedures for possible instruction types.

Const InstructionProc: Array [0..53] of Procedure = (
 { 00 } Proc_NoParameters,
 { 01 } Proc_ImmediateWord,
 { 02 } Proc_ImmediateSignedByte,
 { 03 } Proc_16BitReg_RegMem,
 { 04 } Proc_DX_ACC,
 { 05 } Proc_ImmediateByte_ACC,
 { 06 } Proc_ACC_DX,
 { 07 } Proc_ACC_ImmediateByte,
 { 08 } Proc_16BitReg_AX,
 { 09 } Proc_AX_16BitReg,
 { 0A } Proc_ImmediateByteWithSpecialFor_3,
 { 0B } Proc_ImmediateByte_ImmediateWord,
 { 0C } Proc_ACC_Immediate,
 { 0D } Proc_Reg_Immediate,
 { 0E } Proc_NearIndirect,
 { 0F } Proc_FarIdentifierReference,
 { 10 } Proc_FarIndirect,
 { 11 } Proc_JumpLabel,
 { 12 } Proc_DisplacementIdentifierReference,
 { 13 } Proc_MemAddress_ACC,
 { 14 } Proc_ACC_MemAddress,
 { 15 } Proc_ImmediateWithSpecialFor_0_OrNoParameter,
 { 16 } Proc_ImmediateWithSpecialFor_0,
 { 17 } Proc_SyntaxError,
 { 18 } Proc_SegmentRegister,
 { 19 } Proc_SegmentRegisterExcept_CS,
 { 1A } Proc_16BitReg,
 { 1B } Proc_DescriptorTable,
 { 1C } Proc_16BitReg_16BitRegMem,
 { 1D } Proc_16BitRegMem_16BitReg,
 { 1E } Proc_Reg_RegMem_Immediate,
 { 1F } Proc_SegmentReg_RegMem,
 { 20 } Proc_RegMem_SegmentReg,
 { 21 } Proc_ByteOrWord_RegMem_Reg,
 { 22 } Proc_ByteOrWord_RegMem_Reg_Or_Reg_RegMem,
 { 23 } Proc_16bit_RegisterOrMemory,
 { 24 } Proc_RegMem_ImmediateSignedByteOrWord,
 { 25 } Proc_RegMem__Immediate,
 { 26 } Proc_UnaryOperations,
 { 27 } Proc_16BitReg_PointerMemoryReference,
 { 28 } Proc_ImmediateWithSpecialFor_1_Or_CL,
 { 29 } Proc_FPU_Instruction,
 { 2A } Proc_AX,
 { 2B } Proc_STi,
 { 2C } Proc_STi_ST,
 { 2D } Proc_ST_STi,
 { 2E } Proc_real32_or_real64,
 { 2F } Proc_real80,
 { 30 } Proc_int16,
 { 31 } Proc_int16_or_int32,
 { 32 } Proc_int64,
 { 33 } Proc_MemoryReferenceSize_14,
 { 34 } Proc_MemoryReferenceSize_94,
 { 35 } Proc_SyntaxError);

These opcode generation procedures actually generate opcodes for assembler instructions.

Procedure Proc_NoParameters; Far;
begin
  GenerateOpCodesExceptLastBeforeData;
  InstructionProcessed := True;
end;

Procedure Proc_ImmediateWord; Far;
begin
  GenerateOpCodesExceptLastBeforeData;
  SwapLeftAndRightExpression;
  InstructionProcessed := GenerateImmediateWord;
end;

Procedure Proc_ImmediateSignedByte; Far;
begin
  SwapLeftAndRightExpression;
  GenerateOpCodesExceptLastBeforeData;
  If not RightExpressionSignedByteConstant then Exit;
  GenerateLastOpCodeBeforeDataAnd_acByte (RightExpression^.Value.Byte);
  InstructionProcessed := True;
end;

Procedure Proc_16BitReg_RegMem; Far;
begin
  If InstructionTokens <> Register_MemoryReference then Exit;
  If LeftExpression^.RegisterType <> rt16BitRegister then Exit;
  SwapLeftAndRightExpression;
  If not LeftExpressionRegMem then Exit;
  SwapLeftAndRightExpression;
  SegmentOverrideOpCode := 0;
  GenerateOpCodesExceptLastBeforeData;
  ModemOpcode := ModemOpcode or LeftExpression^.Register shl 3;
  InstructionProcessed := ClearLeftExprTypeSizeAndGenerateRestOfInstruction;
end;

Procedure Proc_ACC_DX; Far;
begin
  With RightExpression^ do
    begin
      If Token <> AsmToken_Register then Exit;
      If RegisterType <> rt16BitRegister then Exit;
      If Register <> rDX then Exit;
    end;
  InstructionProcessed := IsLeftExpression_ACC;
end;

Procedure Proc_DX_ACC; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  Proc_ACC_DX;
end;

Procedure Proc_ACC_ImmediateByte; Far;
begin
  If not IsLeftExpression_ACC then Exit;
  InstructionProcessed := GenerateImmediateByte;
end;

Procedure Proc_ImmediateByte_ACC; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  Proc_ACC_ImmediateByte;
end;

Procedure Proc_AX_16BitReg; Far;
begin
  If InstructionTokens <> Register_Register then Exit;
  If LeftExpression^.RegisterType <> rt16BitRegister then Exit;
  If LeftExpression^.Register <> rAX then Exit;
  If RightExpression^.RegisterType <> rt16BitRegister then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or RightExpression^.Register;
  InstructionProcessed := True;
end;

Procedure Proc_16BitReg_AX; Far;
begin
  SwapLeftAndRightExpression;
  Proc_AX_16BitReg;
end;

Procedure Proc_ImmediateByteWithSpecialFor_3; Far;
begin
  GenerateOpCodesExceptLastBeforeData;
  RightExpression := LeftExpression;
  If not RightExpressionNumericConstantAndSize8Bit then Exit;
  If LeftExpression^.Value.Byte <> $03 then
    begin
      Inc (LastOpCodeBeforeModem);
      GenerateLastOpCodeBeforeDataAnd_acByte (LeftExpression^.Value.Byte);
    end;
  InstructionProcessed := True;
end;

Procedure Proc_ImmediateByte_ImmediateWord; Far;
begin
  SwapLeftAndRightExpression;
  GenerateOpCodesExceptLastBeforeData;
  If not GenerateImmediateWord then Exit;
  SwapLeftAndRightExpression;
  InstructionProcessed := GenerateImmediateByte;
end;

Procedure Proc_ACC_Immediate; Far;
begin
  If InstructionTokens <> Register_Constant then Exit;
  If not RightExpression16BitNumericConstant then Exit;
  With LeftExpression^ do
    begin
      If (Register <> rACC) or (RegisterType > rt16BitRegister) then Exit;
      Case RegisterType of
        rt8BitRegister: begin
                          If not RightExpressionNumericConstantAndSize8Bit then Exit;
                          GenerateOpCodesExceptLastBeforeData;
                          InstructionProcessed := GenerateImmediateByte;
                        end;
        rt16BitRegister: begin
                           GenerateOpCodesExceptLastBeforeData;
                           Inc (LastOpCodeBeforeModem);
                           InstructionProcessed := GenerateImmediateWord;
                         end;
      end;
    end;
end;

Procedure Proc_Reg_Immediate; Far;
begin
  With LeftExpression^ do
    begin
      If InstructionTokens <> Register_Constant then Exit;
      If RegisterType > rt16BitRegister then Exit;
      GenerateOpCodesExceptLastBeforeData;
      LastOpCodeBeforeModem := LastOpCodeBeforeModem or Register;
      Case RegisterType of
        rt8BitRegister: InstructionProcessed := GenerateImmediateByte;
        rt16BitRegister: begin
                           LastOpCodeBeforeModem := LastOpCodeBeforeModem or $08;
                           InstructionProcessed := GenerateImmediateWord;
                         end;
      end;
    end;
end;

Procedure Proc_NearIndirect; Far;
begin
  If not LeftExpressionRegMem then Exit;
  If LeftExpressionTypeSize <> Ord (rt16BitRegister) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LeftExpressionTypeSize := 0;
  If not GenerateRestOf_RegMem__Register_Instruction then Exit;
  InstructionProcessed := True;
end;

Procedure Proc_FarIdentifierReference; Far;
begin
  GenerateInstructionWithIdentifierReference (3, $FFFE);
end;

Procedure Proc_FarIndirect; Far;
begin
  If not LeftExpressionRegMem then Exit;
  If LeftExpressionTypeSize <> $FF then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LeftExpressionTypeSize := 0;
  InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
end;

Procedure Proc_JumpLabel; Far;
begin
  With LeftExpression^ do
    begin
      If Token <> AsmToken_MemoryReference then Exit;
      If TypeSize <> $FFFD then Exit;
      If MemoryReferences <> [mrMemoryLocation] then Exit;
      If Value.LongInt <> 0 then Exit;
      GeneratePrefixOpCodes;
      CurrentRelocatableIdentifier.Long := RelocatableIdentifier;
      AddAsmIntermediateCodeRecord (acJumpNear, 0, InstructionData^.Data [0], Byte (AsmToken));
    end;
  InstructionProcessed := True;
end;

Procedure Proc_DisplacementIdentifierReference; Far;
begin
  If LeftExpression^.TypeSize = $FFFD then
    GenerateInstructionWithIdentifierReference (0, $FFFD) else
      GenerateInstructionWithIdentifierReference (0, $FFFF);
end;

Procedure Proc_MemAddress_ACC; Far;
begin
  If InstructionTokens <> MemoryReference_Register then Exit;
  If RightExpression^.Register <> rACC then Exit;
  If not LeftExpressionRegMem then Exit;
  If RegisterInMemoryReference then Exit;
  GenerateOpCodesExceptLastBeforeData;
  If RightExpression^.RegisterType > rt16BitRegister then Exit;
  If Ord (RightExpression^.RegisterType) <> LeftExpressionTypeSize then Exit;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or Ord (RightExpression^.RegisterType);
  Generate16BitDisplacement;
  InstructionProcessed := True;
end;

Procedure Proc_ACC_MemAddress; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  Proc_MemAddress_ACC;
end;

Procedure Proc_ImmediateWithSpecialFor_0_OrNoParameter; Far;
begin
  GenerateOpCodesExceptLastBeforeData;
  If Flags and $0100 <> 0 then LastOpCodeBeforeModem := LastOpCodeBeforeModem or $08;
  InstructionProcessed := True;
  If ExpressionCounter = 0 then Exit;
  RightExpression := LeftExpression;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or $01;
  If RightExpressionWordConstant_0 then Exit;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem and $FE;
  InstructionProcessed := GenerateImmediateWord;
end;

Procedure Proc_ImmediateWithSpecialFor_0; Far;
begin
  GenerateOpCodesExceptLastBeforeData;
  RightExpression := LeftExpression;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or $01;
  InstructionProcessed := True;
  If RightExpressionWordConstant_0 then Exit;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem and $FE;
  InstructionProcessed := GenerateImmediateWord;
end;

Procedure Proc_SyntaxError; Far;
begin
  AsmError (SyntaxError);
end;

Procedure Proc_SegmentRegister; Far;
begin
  InstructionWithSegmentRegister ($FF);
end;

Procedure Proc_SegmentRegisterExcept_CS; Far;
begin
  InstructionWithSegmentRegister (1);
end;

Procedure Proc_16BitReg; Far;
begin
  If LeftToken <> AsmToken_Register then Exit;
  If LeftExpression^.RegisterType <> rt16BitRegister then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or LeftExpression^.Register;
  InstructionProcessed := True;
end;

Procedure Proc_DescriptorTable; Far;
begin
  If not LeftExpressionRegMem then Exit;
  With LeftExpression^ do If (TypeSize <> 6) and (TypeSize <> 0) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LeftExpressionTypeSize := 0;
  InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
end;

Procedure Proc_16BitRegMem_16BitReg; Far;
begin
  If RightToken <> AsmToken_Register then Exit;
  If RightExpression^.RegisterType <> rt16BitRegister then Exit;
  If not LeftExpressionRegMem then Exit;
  If LeftExpressionTypeSize <> Ord (rt16BitRegister) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  AddRegisterToModemOpcode;
  InstructionProcessed := ClearLeftExprTypeSizeAndGenerateRestOfInstruction;
end;

Procedure Proc_16BitReg_16BitRegMem; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  Proc_16BitRegMem_16BitReg
end;

Procedure Proc_Reg_RegMem_Immediate; Far;
Var IsByte: Boolean;
begin
  If LeftToken <> AsmToken_Register then
  If LeftExpression^.RegisterType <> rt16BitRegister then Exit;
  SwapLeftAndRightExpression;
  If not LeftExpressionRegMem then Exit;
  If LeftExpressionTypeSize <> Ord (rt16BitRegister) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  AddRegisterToModemOpcode;
  RightExpression := @AsmExpression3;
  If not RightExpression16BitNumericConstant then Exit;
  IsByte := RightExpressionSignedByteConstant;
  If IsByte then LastOpCodeBeforeModem := LastOpCodeBeforeModem or $02;
  ClearLeftExprTypeSizeAndGenerateRestOfInstruction;
  If IsByte then GenerateLastOpCodeBeforeDataAnd_acByte (RightExpression^.Value.Byte) else
    begin
      GenerateLastOpCodeBeforeDataAnd_acByte (RightExpression^.Value.Byte);
      GenerateLastOpCodeBeforeDataAnd_acByte (RightExpression^.Value.Byte1);
    end;
  InstructionProcessed := True;
end;

Procedure Proc_RegMem_SegmentReg; Far;
begin
  If RightExpression^.Token <> AsmToken_Register then Exit;
  If RightExpression^.RegisterType <> rtSegmentRegister then Exit;
  If not LeftExpressionRegMem then Exit;
  If (LeftExpressionTypeSize <> 1) and (RightExpression^.TypeSize <> 0) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  AddRegisterToModemOpcode;
  InstructionProcessed := ClearLeftExprTypeSizeAndGenerateRestOfInstruction;
end;

Procedure Proc_SegmentReg_RegMem; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  If RightExpression^.Register <> rCX then Proc_RegMem_SegmentReg;
end;

Procedure Proc_ByteOrWord_RegMem_Reg; Far;
begin
  If RightToken <> AsmToken_Register then
    begin
      If LeftToken <> AsmToken_Register then Exit;
      Direction := 2;
      SwapLeftAndRightExpression;
    end;
  If RightExpression^.RegisterType > rt16BitRegister then Exit;
  If not LeftExpressionByteOrWordRegMem then Exit;
  GenerateOpCodesExceptLastBeforeData;
  AddRegisterToModemOpcode;
  If Byte (RightExpression^.RegisterType) = LeftExpressionTypeSize then InstructionProcessed := GenerateRestOfInstruction;
end;

Procedure Proc_ByteOrWord_RegMem_Reg_Or_Reg_RegMem; Far;

  Function ByteOrWord_RegMem_Reg: Boolean;
  begin
    ByteOrWord_RegMem_Reg := False;
    If RightToken <> AsmToken_Register then Exit;
    If RightExpression^.RegisterType > rt16BitRegister then Exit;
    If not LeftExpressionByteOrWordRegMem then Exit;
    GenerateOpCodesExceptLastBeforeData;
    AddRegisterToModemOpcode;
    If Byte (RightExpression^.RegisterType) <> LeftExpressionTypeSize then Exit;
    ByteOrWord_RegMem_Reg := GenerateRestOfInstruction;
  end;

begin
  InstructionProcessed := True;
  If ByteOrWord_RegMem_Reg then Exit;
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  InstructionProcessed := ByteOrWord_RegMem_Reg;
end;

Procedure Proc_16bit_RegisterOrMemory; Far;
begin
  If not LeftExpressionRegMem then Exit;
  If LeftExpressionTypeSize <> Ord (rt16BitRegister) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  LeftExpressionTypeSize := 0;
  InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
end;

Procedure Proc_RegMem_ImmediateSignedByteOrWord; Far;
begin
  If not RightExpression16BitNumericConstant then Exit;
  If not LeftExpressionByteOrWordRegMem then Exit;
  GenerateOpCodesExceptLastBeforeData;
  If LeftExpressionTypeSize <> 0 then
    begin
      If not RightExpressionSignedByteConstant then
        begin
          If not GenerateRestOf_RegMem__Register_Instruction then Exit;
          InstructionProcessed := GenerateImmediateWord;
          Exit;
        end;
      LastOpCodeBeforeModem := LastOpCodeBeforeModem or $02;
    end;
  If not RightExpressionNumericConstantAndSize8Bit then Exit;
  If not GenerateRestOf_RegMem__Register_Instruction then Exit;
  InstructionProcessed := GenerateImmediateByte;
end;

Procedure Proc_RegMem__Immediate; Far;
begin
  If RightToken <> AsmToken_Constant then Exit;
  If not LeftExpressionByteOrWordRegMem then Exit;
  GenerateOpCodesExceptLastBeforeData;
  GenerateRestOf_RegMem__Register_Instruction;
  Case LeftExpressionTypeSize of
    1: InstructionProcessed := GenerateImmediateWord;
    else InstructionProcessed := GenerateImmediateByte;
  end;
end;

Procedure Proc_UnaryOperations; Far;
begin
  If not LeftExpressionByteOrWordRegMem then Exit;
  GenerateOpCodesExceptLastBeforeData;
  If not GenerateRestOf_RegMem__Register_Instruction then Exit;
  InstructionProcessed := True;
end;

Procedure Proc_16BitReg_PointerMemoryReference; Far;
begin
  If InstructionTokens <> Register_MemoryReference then Exit;
  If LeftExpression^.RegisterType <> rt16BitRegister then Exit;
  SwapLeftAndRightExpression;
  LeftExpressionRegMem;
  If (SavedRightExpressionTypeSize <> 0) and (LeftExpressionTypeSize <> $FF) then Exit;
  GenerateOpCodesExceptLastBeforeData;
  AddRegisterToModemOpcode;
  InstructionProcessed := ClearLeftExprTypeSizeAndGenerateRestOfInstruction;
end;

Procedure Proc_ImmediateWithSpecialFor_1_Or_CL; Far;
begin
  If not LeftExpressionByteOrWordRegMem then Exit;
  GenerateOpCodesExceptLastBeforeData;
  If RightExpressionNumericConstantAndSize8Bit then
    begin
      If RightExpression^.Value.Byte <> 1 then
        begin
          If Flags and $0003 = 0 then AsmError (_286_287_InstructionsAreNotEnabled);
          Dec (LastOpCodeBeforeModem, $10);
          GenerateRestOf_RegMem__Register_Instruction;
          GenerateLastOpCodeBeforeDataAnd_acByte (RightExpression^.Value.Byte);
          InstructionProcessed := True;
        end else InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
    end else begin
               If RightExpression^.Token <> AsmToken_Register then Exit;
               If RightExpression^.RegisterType <> rt8BitRegister then Exit;
               If RightExpression^.Register <> rCL then Exit;
               Inc (LastOpCodeBeforeModem, 2);
               InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
             end;
end;

Procedure Proc_FPU_Instruction;
begin
  ModifyAndGenerate_FPU_Instruction (0)
end;

Procedure Proc_AX; Far;
begin
  If LeftToken <> AsmToken_Register then Exit;
  With Leftexpression^ do
    begin
      If RegisterType <> rt16BitRegister then Exit;
      If Register <> rAX then Exit;
    end;
  ModifyAndGenerate_FPU_Instruction (0)
end;

Procedure Process_FPU_Instruction__STi;
begin
  If InstructionTokens <> Register_Register then Exit;
  If LeftExpression^.RegisterType <> rtFPURegister then Exit;
  Proc_FPU_Instruction;
  LastOpCodeBeforeModem := LastOpCodeBeforeModem or LeftExpression^.Register;
  InstructionProcessed := True;
end;

Procedure Proc_STi; Far;
begin
  RightToken := AsmToken_Register;
  Process_FPU_Instruction__STi;
end;

Procedure Proc_STi_ST; Far;
begin
  With RightExpression^ do If (RegisterType <> rtFPURegister) or (Register <> 0) then Exit;
  Process_FPU_Instruction__STi;
end;

Procedure Proc_ST_STi; Far;
begin
  SwapLeftAndRightExpression;
  InstructionTokens := Swap (InstructionTokens);
  Proc_STi_ST;
end;

Procedure FPU_Instruction_Size1_or_Size2 (Size: Word);
Var RealSizeModifier: Byte;
begin
  If LeftToken <> AsmToken_MemoryReference then Exit;
  If not LeftExpressionRegMem then Exit;
  RealSizeModifier := 0;
  If LeftExpressionTypeSize <> Hi (Size) then
    begin
      If LeftExpressionTypeSize <> Lo (Size) then Exit;
      RealSizeModifier := $04;
    end;
  ModifyAndGenerate_FPU_Instruction (RealSizeModifier);
  LeftExpressionTypeSize := 0;
  InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
end;

Procedure Proc_real32_or_real64; Far;
begin
  FPU_Instruction_Size1_or_Size2 ($FFFE);
end;

Procedure Proc_real80; Far;
begin
  FPU_Instruction_Size1_or_Size2 ($FDFD);
end;

Procedure Proc_int16; Far;
begin
  With LeftExpression^ do
    If TypeSize = 0 then TypeSize := 2;
  FPU_Instruction_Size1_or_Size2 ($0101);
end;

Procedure Proc_int16_or_int32; Far;
begin
  FPU_Instruction_Size1_or_Size2 ($FF01);
end;

Procedure Proc_int64; Far;
begin
  FPU_Instruction_Size1_or_Size2 ($FEFE);
end;

Procedure FPU_Instruction__MemoryReferenceSize (Size: Word);
begin
  With LeftExpression^ do If (TypeSize <> Size) and (TypeSize <> 0) then Exit;
  If LeftToken <> AsmToken_MemoryReference then Exit;
  If not LeftExpressionRegMem then Exit;
  Proc_FPU_Instruction;
  LeftExpressionTypeSize := 0;
  InstructionProcessed := GenerateRestOf_RegMem__Register_Instruction;
end;

Procedure Proc_MemoryReferenceSize_14; Far;
begin
  FPU_Instruction__MemoryReferenceSize ($000E);
end;

Procedure Proc_MemoryReferenceSize_94; Far;
begin
  FPU_Instruction__MemoryReferenceSize ($005E);
end;