switch.java

一种将c高级语言转化给VHDL的编译器

/*
 *
 LA-CC 05-135 Trident 0.7.1

Copyright Notice
Copyright 2006 (c) the Regents of the University of California.

This Software was produced under a U.S. Government contract
(W-7405-ENG-36) by Los Alamos National Laboratory, which is operated
by the University of California for the U.S. Department of Energy. The
U.S. Government is licensed to use, reproduce, and distribute this
Software. Permission is granted to the public to copy and use this
Software without charge, provided that this Notice and any statement
of authorship are reproduced on all copies. Neither the Government nor
the University makes any warranty, express or implied, or assumes any
liability or responsibility for the user of this Software.


 */


package fp.flowgraph;

import java.util.*;

import fp.util.BooleanEquation;

public class Switch extends InstructionFormat {

  private static final int getValue(int i) { return 2*i+2; }
  private static final int getLabel(int i) { return 2*i+3; }


  public static boolean conforms(Instruction i) {
    return conforms(i.operator);
  }

  public static boolean conforms(Operator op) {
    return op.format == Switch_format;
  }
  

  public static Operand getTest(Instruction i) {
    return i.getOperand(0);
  }

  public static void setTest(Instruction i, Operand value) {
    i.putOperand(0, value);
  }

  public static boolean hasTest(Instruction i) {
    return i.getOperand(0) != null;
  }


  public static LabelOperand getDefault(Instruction i) {
    return (LabelOperand)i.getOperand(1);
  }

  public static void setDefault(Instruction i, LabelOperand label) {
    i.putOperand(1, label);
  }

  public static boolean hasDefault(Instruction i) {
     return i.getOperand(1) != null;
  }


  public static LabelOperand getCaseLabel(Instruction i, int index) {
    return (LabelOperand)i.getOperand(getLabel(index));
  }

  public static ConstantOperand getCaseValue(Instruction i, int index) {
    return (ConstantOperand)i.getOperand(getValue(index));
  }

  public static void setCase(Instruction i, int index, ConstantOperand value, LabelOperand label) {
    i.putOperand(getValue(index), value);
    i.putOperand(getLabel(index), label);
  }

  public static boolean hasCase(Instruction i, int index) {
    return i.getOperand(getValue(index)) != null;
  }


  public static Instruction create(Operator o, Type type, Operand variable, LabelOperand def,
				   LinkedList cases) {
    return Switch.create(o, type, variable, def, cases, null);
  }

  public static Instruction create(Operator o, Type type, Operand variable, LabelOperand def,
                                   LinkedList cases, BooleanEquation eq) {
    Instruction i = new Instruction(o, type, eq);
    i.putOperand(0, variable);
    i.putOperand(1, def);

    if (cases != null) {
      i.resizeNumberOfOperands( cases.size() + 5 );
      
      int index = 0;
      
      for(ListIterator iter = cases.listIterator(); iter.hasNext(); ) {
	ConstantOperand value = (ConstantOperand)iter.next();
	LabelOperand label = (LabelOperand)iter.next();
	i.putOperand(getValue(index), value);
	i.putOperand(getLabel(index), label);
	index++;
      }
    }
    return i;
  }

  public static void verify(Instruction i) throws IllegalOperand {
    if (!hasTest(i)) {
      throw new IllegalOperand("Switch instruction does not have a test operand.");
    }
    if (!getTest(i).isIntegerOperand()) {
	throw new IllegalOperand("Switch instruction test operand is not integer operand.");
      }
    if (!hasDefault(i)) {
      throw new IllegalOperand("Switch instruction does not have a default label operand.");
    }
    if (!getDefault(i).isLabel()) {
      throw new IllegalOperand("Switch instruction default is not a label operand.");
    }

    int index = 0;
    while (hasCase(i, index)) {
      Operand value = getCaseValue(i, index);
      Operand label = getCaseLabel(i, index);
      if ((label==null) || (value==null)) {
	throw new IllegalOperand("Switch instruction missing operand in its value/label pairs");
      }
      if (!label.isLabel()) {
	throw new IllegalOperand("Switch instruction case label operand " + label.getName() + " is not label.");
      }
      if (!value.isIntegerOperand()) {
	throw new IllegalOperand("Switch instruction case value operand " + value.getName() + " is not integer operand.");
      }
      index++;
    }
  }

}