code: /**
   * Copyright (c) 2004-2005, Regents of the University of California
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * Neither the name of the University of California, Los Angeles nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package avrora.sim.util;
  
  import avrora.sim.*;
  import cck.text.Terminal;
  
  
  /**
   * <code>MemTimer</code> lets simulated applications start and stop
   * timers
   *
   * @author John Regehr
   */
  public class MemTimer extends Simulator.Watch.Empty {
  
      int base;
      long start_time = 0;
      int timer_state = 0;
  
      public MemTimer(int b) {
          base = b;
      }
  
      public void fireBeforeWrite(State state, int data_addr, byte value) {
          if (data_addr != base) {
              Terminal.printRed("Unexpected interception by printer!");
              System.exit(-1);
          }
          
          switch (value) {
              case 100:
                  if (timer_state != 0) {
                      Terminal.printRed("timer: multiple starts in a row??");
                      Terminal.nextln();
                  } else {
                      start_time = state.getCycles();
                  }
                  timer_state = 1;
                  break;
              case 101:
                  if (timer_state != 1) {
                      Terminal.printRed("timer: multiple stops in a row??");
                      Terminal.nextln();
                  } else {
                      long stop_time = state.getCycles();
                      long duration = stop_time - start_time;
                      Terminal.printRed("timer: " + String.valueOf(duration) + " cycles");
                      Terminal.nextln();
                  }
                  timer_state = 0;
                  break;
              default:
                  Terminal.printRed("Unexpected command to timer!");
                  Terminal.nextln();
          }
      }
  }
  