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 */
013package org.mmtk.utility.deque;
014
015import org.mmtk.vm.VM;
016import org.vmmagic.pragma.Uninterruptible;
017import org.vmmagic.unboxed.Address;
018
019
020/**
021 * This supports <i>unsynchronized</i> enqueuing and dequeuing of
022 * address triples
023 */
024@Uninterruptible public class AddressTripleDeque extends LocalDeque {
025
026  /****************************************************************************
027   *
028   * Public instance methods
029   */
030
031  /**
032   * Constructor
033   *
034   * @param queue The shared queue to which this queue will append its
035   * buffers (when full or flushed) and from which it will acquire new
036   * buffers when it has exhausted its own.
037   */
038  AddressTripleDeque(SharedDeque queue) {
039    super(queue);
040  }
041
042  /**
043   * Insert an address triple into the address queue.
044   *
045   * @param addr1 the first address to be inserted into the address queue
046   * @param addr2 the second address to be inserted into the address queue
047   * @param addr3 the third address to be inserted into the address queue
048   */
049  public final void insert(Address addr1, Address addr2,
050                           Address addr3) {
051    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr1.isZero());
052    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr2.isZero());
053    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr3.isZero());
054    checkTailInsert(3);
055    uncheckedTailInsert(addr1);
056    uncheckedTailInsert(addr2);
057    uncheckedTailInsert(addr3);
058  }
059  /**
060   * Push an address pair onto the address queue.
061   *
062   * @param addr1 the first value to be pushed onto the address queue
063   * @param addr2 the second value to be pushed onto the address queue
064   * @param addr3 the third address to be pushed onto the address queue
065   */
066  public final void push(Address addr1, Address addr2, Address addr3) {
067    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr1.isZero());
068    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr2.isZero());
069    if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!addr3.isZero());
070    checkHeadInsert(3);
071    uncheckedHeadInsert(addr3);
072    uncheckedHeadInsert(addr2);
073    uncheckedHeadInsert(addr1);
074  }
075
076  /**
077   * Pop the first address in a triple from the address queue, return
078   * zero if the queue is empty.
079   *
080   * @return The next address in the address queue, or zero if the
081   * queue is empty
082   */
083  public final Address pop1() {
084    if (checkDequeue(3))
085      return uncheckedDequeue();
086    else
087      return Address.zero();
088  }
089
090  /**
091   * Pop the second address in a triple from the address queue.
092   *
093   * @return The next address in the address queue
094   */
095  public final Address pop2() {
096    return uncheckedDequeue();
097  }
098
099
100  /**
101   * Pop the third address in a triple from the address queue.
102   *
103   * @return The next address in the address queue
104   */
105  public final Address pop3() {
106    return uncheckedDequeue();
107  }
108}