encoder.java

The triangle language processor will be consist of a compiler, an interpreter, and a disassembler

  }

  public Object visitTypeDeclaration(TypeDeclaration ast, Object o) {
    // just to ensure the type's representation is decided
    ast.T.visit(this, null);
    return new Integer(0);
  }

  public Object visitUnaryOperatorDeclaration(UnaryOperatorDeclaration ast,
					      Object o) {
    return new Integer(0);
  }

  public Object visitVarDeclaration(VarDeclaration ast, Object o) {
    Frame frame = (Frame) o;
    int extraSize;

    extraSize = ((Integer) ast.T.visit(this, null)).intValue();
    emit(Machine.PUSHop, 0, 0, extraSize);
    ast.entity = new KnownAddress(Machine.addressSize, frame.level, frame.size);
    writeTableDetails(ast);
    return new Integer(extraSize);
  }


  // Array Aggregates
  public Object visitMultipleArrayAggregate(MultipleArrayAggregate ast,
					    Object o) {
    Frame frame = (Frame) o;
    int elemSize = ((Integer) ast.E.visit(this, frame)).intValue();
    Frame frame1 = new Frame(frame, elemSize);
    int arraySize = ((Integer) ast.AA.visit(this, frame1)).intValue();
    return new Integer(elemSize + arraySize);
  }

  public Object visitSingleArrayAggregate(SingleArrayAggregate ast, Object o) {
    return ast.E.visit(this, o);
  }


  // Record Aggregates
  public Object visitMultipleRecordAggregate(MultipleRecordAggregate ast,
					     Object o) {
    Frame frame = (Frame) o;
    int fieldSize = ((Integer) ast.E.visit(this, frame)).intValue();
    Frame frame1 = new Frame (frame, fieldSize);
    int recordSize = ((Integer) ast.RA.visit(this, frame1)).intValue();
    return new Integer(fieldSize + recordSize);
  }

  public Object visitSingleRecordAggregate(SingleRecordAggregate ast,
					   Object o) {
    return ast.E.visit(this, o);
  }


  // Formal Parameters
  public Object visitConstFormalParameter(ConstFormalParameter ast, Object o) {
    Frame frame = (Frame) o;
    int valSize = ((Integer) ast.T.visit(this, null)).intValue();
    ast.entity = new UnknownValue (valSize, frame.level, -frame.size - valSize);
    writeTableDetails(ast);
    return new Integer(valSize);
  }

  public Object visitFuncFormalParameter(FuncFormalParameter ast, Object o) {
    Frame frame = (Frame) o;
    int argsSize = Machine.closureSize;
    ast.entity = new UnknownRoutine (Machine.closureSize, frame.level,
				  -frame.size - argsSize);
    writeTableDetails(ast);
    return new Integer(argsSize);
  }

  public Object visitProcFormalParameter(ProcFormalParameter ast, Object o) {
    Frame frame = (Frame) o;
    int argsSize = Machine.closureSize;
    ast.entity = new UnknownRoutine (Machine.closureSize, frame.level,
				  -frame.size - argsSize);
    writeTableDetails(ast);
    return new Integer(argsSize);
  }

  public Object visitVarFormalParameter(VarFormalParameter ast, Object o) {
    Frame frame = (Frame) o;
    ast.T.visit(this, null);
    ast.entity = new UnknownAddress (Machine.addressSize, frame.level,
				  -frame.size - Machine.addressSize);
    writeTableDetails(ast);
    return new Integer(Machine.addressSize);
  }


  public Object visitEmptyFormalParameterSequence(
	 EmptyFormalParameterSequence ast, Object o) {
    return new Integer(0);
  }

  public Object visitMultipleFormalParameterSequence(
 	 MultipleFormalParameterSequence ast, Object o) {
    Frame frame = (Frame) o;
    int argsSize1 = ((Integer) ast.FPS.visit(this, frame)).intValue();
    Frame frame1 = new Frame(frame, argsSize1);
    int argsSize2 = ((Integer) ast.FP.visit(this, frame1)).intValue();
    return new Integer(argsSize1 + argsSize2);
  }

  public Object visitSingleFormalParameterSequence(
	 SingleFormalParameterSequence ast, Object o) {
    return ast.FP.visit (this, o);
  }


  // Actual Parameters
  public Object visitConstActualParameter(ConstActualParameter ast, Object o) {
    return ast.E.visit (this, o);
  }

  public Object visitFuncActualParameter(FuncActualParameter ast, Object o) {
    Frame frame = (Frame) o;
    if (ast.I.decl.entity instanceof KnownRoutine) {
      ObjectAddress address = ((KnownRoutine) ast.I.decl.entity).address;
      // static link, code address
      emit(Machine.LOADAop, 0, displayRegister(frame.level, address.level), 0);
      emit(Machine.LOADAop, 0, Machine.CBr, address.displacement);
    } else if (ast.I.decl.entity instanceof UnknownRoutine) {
      ObjectAddress address = ((UnknownRoutine) ast.I.decl.entity).address;
      emit(Machine.LOADop, Machine.closureSize, displayRegister(frame.level,
           address.level), address.displacement);
    } else if (ast.I.decl.entity instanceof PrimitiveRoutine) {
      int displacement = ((PrimitiveRoutine) ast.I.decl.entity).displacement;
      // static link, code address
      emit(Machine.LOADAop, 0, Machine.SBr, 0);
      emit(Machine.LOADAop, 0, Machine.PBr, displacement);
    }
    return new Integer(Machine.closureSize);
  }

  public Object visitProcActualParameter(ProcActualParameter ast, Object o) {
    Frame frame = (Frame) o;
    if (ast.I.decl.entity instanceof KnownRoutine) {
      ObjectAddress address = ((KnownRoutine) ast.I.decl.entity).address;
      // static link, code address
      emit(Machine.LOADAop, 0, displayRegister(frame.level, address.level), 0);
      emit(Machine.LOADAop, 0, Machine.CBr, address.displacement);
    } else if (ast.I.decl.entity instanceof UnknownRoutine) {
      ObjectAddress address = ((UnknownRoutine) ast.I.decl.entity).address;
      emit(Machine.LOADop, Machine.closureSize, displayRegister(frame.level,
           address.level), address.displacement);
    } else if (ast.I.decl.entity instanceof PrimitiveRoutine) {
      int displacement = ((PrimitiveRoutine) ast.I.decl.entity).displacement;
      // static link, code address
      emit(Machine.LOADAop, 0, Machine.SBr, 0);
      emit(Machine.LOADAop, 0, Machine.PBr, displacement);
    }
    return new Integer(Machine.closureSize);
  }

  public Object visitVarActualParameter(VarActualParameter ast, Object o) {
    encodeFetchAddress(ast.V, (Frame) o);
    return new Integer(Machine.addressSize);
  }


  public Object visitEmptyActualParameterSequence(
	 EmptyActualParameterSequence ast, Object o) {
    return new Integer(0);
  }

  public Object visitMultipleActualParameterSequence(
	 MultipleActualParameterSequence ast, Object o) {
    Frame frame = (Frame) o;
    int argsSize1 = ((Integer) ast.AP.visit(this, frame)).intValue();
    Frame frame1 = new Frame (frame, argsSize1);
    int argsSize2 = ((Integer) ast.APS.visit(this, frame1)).intValue();
    return new Integer(argsSize1 + argsSize2);
  }

  public Object visitSingleActualParameterSequence(
	 SingleActualParameterSequence ast, Object o) {
    return ast.AP.visit (this, o);
  }


  // Type Denoters
  public Object visitAnyTypeDenoter(AnyTypeDenoter ast, Object o) {
    return new Integer(0);
  }

  public Object visitArrayTypeDenoter(ArrayTypeDenoter ast, Object o) {
    int typeSize;
    if (ast.entity == null) {
      int elemSize = ((Integer) ast.T.visit(this, null)).intValue();
      typeSize = Integer.parseInt(ast.IL.spelling) * elemSize;
      ast.entity = new TypeRepresentation(typeSize);
      writeTableDetails(ast);
    } else
      typeSize = ast.entity.size;
    return new Integer(typeSize);
  }

  public Object visitBoolTypeDenoter(BoolTypeDenoter ast, Object o) {
    if (ast.entity == null) {
      ast.entity = new TypeRepresentation(Machine.booleanSize);
      writeTableDetails(ast);
    }
    return new Integer(Machine.booleanSize);
  }

  public Object visitCharTypeDenoter(CharTypeDenoter ast, Object o) {
    if (ast.entity == null) {
      ast.entity = new TypeRepresentation(Machine.characterSize);
      writeTableDetails(ast);
    }
    return new Integer(Machine.characterSize);
  }

  public Object visitErrorTypeDenoter(ErrorTypeDenoter ast, Object o) {
    return new Integer(0);
  }

  public Object visitSimpleTypeDenoter(SimpleTypeDenoter ast,
					   Object o) {
    return new Integer(0);
  }

  public Object visitIntTypeDenoter(IntTypeDenoter ast, Object o) {
    if (ast.entity == null) {
      ast.entity = new TypeRepresentation(Machine.integerSize);
      writeTableDetails(ast);
    }
    return new Integer(Machine.integerSize);
  }

  public Object visitRecordTypeDenoter(RecordTypeDenoter ast, Object o) {
    int typeSize;
    if (ast.entity == null) {
      typeSize = ((Integer) ast.FT.visit(this, new Integer(0))).intValue();
      ast.entity = new TypeRepresentation(typeSize);
      writeTableDetails(ast);
    } else
      typeSize = ast.entity.size;
    return new Integer(typeSize);
  }


  public Object visitMultipleFieldTypeDenoter(MultipleFieldTypeDenoter ast,
					      Object o) {
    int offset = ((Integer) o).intValue();
    int fieldSize;

    if (ast.entity == null) {
      fieldSize = ((Integer) ast.T.visit(this, null)).intValue();
      ast.entity = new Field (fieldSize, offset);
      writeTableDetails(ast);
    } else
      fieldSize = ast.entity.size;

    Integer offset1 = new Integer(offset + fieldSize);
    int recSize = ((Integer) ast.FT.visit(this, offset1)).intValue();
    return new Integer(fieldSize + recSize);
  }

  public Object visitSingleFieldTypeDenoter(SingleFieldTypeDenoter ast,
					    Object o) {
    int offset = ((Integer) o).intValue();
    int fieldSize;

    if (ast.entity == null) {
      fieldSize = ((Integer) ast.T.visit(this, null)).intValue();
      ast.entity = new Field (fieldSize, offset);
      writeTableDetails(ast);
    } else
      fieldSize = ast.entity.size;

    return new Integer(fieldSize);
  }


  // Literals, Identifiers and Operators
  public Object visitCharacterLiteral(CharacterLiteral ast, Object o) {
    return null;
  }

  public Object visitIdentifier(Identifier ast, Object o) {
    Frame frame = (Frame) o;
    if (ast.decl.entity instanceof KnownRoutine) {
      ObjectAddress address = ((KnownRoutine) ast.decl.entity).address;
      emit(Machine.CALLop, displayRegister(frame.level, address.level),
	   Machine.CBr, address.displacement);
    } else if (ast.decl.entity instanceof UnknownRoutine) {
      ObjectAddress address = ((UnknownRoutine) ast.decl.entity).address;
      emit(Machine.LOADop, Machine.closureSize, displayRegister(frame.level,
           address.level), address.displacement);
      emit(Machine.CALLIop, 0, 0, 0);
    } else if (ast.decl.entity instanceof PrimitiveRoutine) {
      int displacement = ((PrimitiveRoutine) ast.decl.entity).displacement;
      if (displacement != Machine.idDisplacement)
        emit(Machine.CALLop, Machine.SBr, Machine.PBr, displacement);
    } else if (ast.decl.entity instanceof EqualityRoutine) { // "=" or "\="
      int displacement = ((EqualityRoutine) ast.decl.entity).displacement;
      emit(Machine.LOADLop, 0, 0, frame.size / 2);
      emit(Machine.CALLop, Machine.SBr, Machine.PBr, displacement);
    }
    return null;
  }

  public Object visitIntegerLiteral(IntegerLiteral ast, Object o) {
    return null;
  }

  public Object visitOperator(Operator ast, Object o) {
    Frame frame = (Frame) o;
    if (ast.decl.entity instanceof KnownRoutine) {
      ObjectAddress address = ((KnownRoutine) ast.decl.entity).address;
      emit(Machine.CALLop, displayRegister (frame.level, address.level),
	   Machine.CBr, address.displacement);
    } else if (ast.decl.entity instanceof UnknownRoutine) {
      ObjectAddress address = ((UnknownRoutine) ast.decl.entity).address;
      emit(Machine.LOADop, Machine.closureSize, displayRegister(frame.level,
           address.level), address.displacement);
      emit(Machine.CALLIop, 0, 0, 0);
    } else if (ast.decl.entity instanceof PrimitiveRoutine) {
      int displacement = ((PrimitiveRoutine) ast.decl.entity).displacement;
      if (displacement != Machine.idDisplacement)
        emit(Machine.CALLop, Machine.SBr, Machine.PBr, displacement);
    } else if (ast.decl.entity instanceof EqualityRoutine) { // "=" or "\="
      int displacement = ((EqualityRoutine) ast.decl.entity).displacement;
      emit(Machine.LOADLop, 0, 0, frame.size / 2);
      emit(Machine.CALLop, Machine.SBr, Machine.PBr, displacement);
    }
    return null;
  }