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.baseline;
014    
015    /**
016     * Profile data for a branch instruction.
017     */
018    public final class ConditionalBranchProfile extends BranchProfile {
019    
020      final float taken;
021      final boolean backwards;
022    
023      /**
024       * @param _bci the bytecode index of the source branch instruction
025       * @param yea the number of times the branch was taken
026       * @param nea the number of times the branch was not taken
027       * @param bw is this a backwards branch?
028       */
029      ConditionalBranchProfile(int _bci, int yea, int nea, boolean bw) {
030        super(_bci, ((float) yea + (float) nea));
031        taken = (float) yea;
032        backwards = bw;
033      }
034    
035      public float getTakenProbability() {
036        if (freq > 0) {
037          return taken / freq;
038        } else if (backwards) {
039          return 0.9f;
040        } else {
041          return 0.5f;
042        }
043      }
044    
045      public String toString() {
046        String ans = bci + (backwards ? "\tbackbranch" : "\tforwbranch");
047        ans += " < " + (int) taken + ", " + (int) (freq - taken) + " > ";
048        if (freq > 0) {
049          ans += (100.0f * taken / freq) + "% taken";
050        } else {
051          ans += "Never Executed";
052        }
053        return ans;
054      }
055    
056    }