001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.compilers.opt.ir.operand;
014    
015    import org.jikesrvm.classloader.TypeReference;
016    import org.jikesrvm.compilers.opt.util.Bits;
017    import org.jikesrvm.runtime.Statics;
018    import org.vmmagic.unboxed.Offset;
019    
020    /**
021     * Represents a constant long operand.
022     *
023     * @see Operand
024     */
025    public final class LongConstantOperand extends ConstantOperand {
026    
027      /**
028       * Constant 0, can be copied as convenient
029       */
030      public static final LongConstantOperand zero =
031        new LongConstantOperand(0, Statics.slotAsOffset(Statics.findOrCreateLongSizeLiteral(0)));
032    
033      /**
034       * Value of this operand.
035       */
036      public long value;
037    
038      /**
039       * Offset in JTOC where this long constant lives. (0 for constants
040       * obtained from constant folding)
041       * //KV: is this field still necessary
042       */
043      public Offset offset;
044    
045      /**
046       * Constructs a new long constant operand with the specified value.
047       *
048       * @param v value
049       */
050      public LongConstantOperand(long v) {
051        value = v;
052        offset = Offset.zero();
053      }
054    
055      /**
056       * Constructs a new long constant operand with the specified value and JTOC offset.
057       * //KV: is this method still necessary
058       * @param v value
059       * @param i offset in the jtoc
060       */
061      public LongConstantOperand(long v, Offset i) {
062        value = v;
063        offset = i;
064      }
065    
066      /**
067       * Return the {@link TypeReference} of the value represented by the operand.
068       *
069       * @return TypeReference.Long
070       */
071      public TypeReference getType() {
072        return TypeReference.Long;
073      }
074    
075      /**
076       * Does the operand represent a value of the long data type?
077       *
078       * @return <code>true</code>
079       */
080      public boolean isLong() {
081        return true;
082      }
083    
084      /**
085       * Return the lower 32 bits (as an int) of value
086       */
087      public int lower32() {
088        return Bits.lower32(value);
089      }
090    
091      /**
092       * Return the upper 32 bits (as an int) of value
093       */
094      public int upper32() {
095        return Bits.upper32(value);
096      }
097    
098      /**
099       * Return a new operand that is semantically equivalent to <code>this</code>.
100       *
101       * @return a copy of <code>this</code>
102       */
103      public Operand copy() {
104        return new LongConstantOperand(value, offset);
105      }
106    
107      /**
108       * Are two operands semantically equivalent?
109       *
110       * @param op other operand
111       * @return   <code>true</code> if <code>this</code> and <code>op</code>
112       *           are semantically equivalent or <code>false</code>
113       *           if they are not.
114       */
115      public boolean similar(Operand op) {
116        return (op instanceof LongConstantOperand) && (value == ((LongConstantOperand) op).value);
117      }
118    
119      /**
120       * Returns the string representation of this operand.
121       *
122       * @return a string representation of this operand.
123       */
124      public String toString() {
125        return Long.toString(value) + "L";
126      }
127    
128    }