code: /**
   * Copyright (c) 2006, 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.
   *
   * Creation date: Feb 26, 2007
   */
  
  package avrora.monitors;
  
  import avrora.sim.Simulator;
  import avrora.sim.State;
  import avrora.sim.output.SimPrinter;
  import avrora.core.SourceMapping;
  import avrora.core.Program;
  import avrora.arch.AbstractInstr;
  import avrora.arch.legacy.*;
  import cck.text.Terminal;
  import cck.text.StringUtil;
  import cck.util.Option;
  
  /**
   * The <code>VirgilMonitor</code> monitor prints a stack trace when the
   * program being simulated executes a break instruction.  This version
   * uses the code in R0 to determine the specific source-level exception
   * that occurred.
   *
   * @author Ben L. Titzer
   */
  public class VirgilMonitor extends MonitorFactory {
  
      public static final int ABORT_TYPE_CODE = 127;
      public static final int ABORT_NULL_CODE = 126;
      public static final int ABORT_BOUNDS_CODE = 125;
      public static final int ABORT_DIV_CODE = 124;
      public static final int ABORT_ALLOC_CODE = 123;
      public static final int ABORT_UNIMP_CODE = 122;
  
      public final Option.Long STATUS_ADDR = newOption("status-addr", 0x91,
              "This option specifies the address in memory where the status register lies. " +
                      "The status register is used to diagnose the cause of a program abort.");
  
      public class Mon implements Monitor {
          public final Simulator simulator;
          public final SimPrinter printer;
          public final CallTrace trace;
          public final CallStack stack;
          private final SourceMapping sourceMap;
  
          Mon(Simulator s) {
              simulator = s;
              printer = s.getPrinter();
  
              trace = new CallTrace(s);
              stack = new CallStack();
              trace.attachMonitor(stack);
  
              Program p = s.getProgram();
              sourceMap = p.getSourceMapping();
              for (int pc = 0; pc < p.program_end; pc = p.getNextPC(pc)) {
                  AbstractInstr i = p.readInstr(pc);
                  if (i != null && i instanceof LegacyInstr.BREAK)
                      s.insertProbe(new BreakProbe(), pc);
              }
          }
  
          public class BreakProbe extends Simulator.Probe.Empty {
  
              public void fireBefore(State state, int pc) {
                  StringBuffer buf = printer.getBuffer();
                  LegacyState s = (LegacyState) simulator.getState();
                  int code = s.getDataByte((int)STATUS_ADDR.get());
                  String name = "UnknownException";
                  String msg = "an unknown exception occurred";
                  switch (code) {
                      case 0: // normal program return from main
                          return;
                      case ABORT_TYPE_CODE:
                          name = "TypeCheckException";
                          msg = "type check exception in explicit cast";
                          break;
                      case ABORT_NULL_CODE:
                          name = "NullCheckException";
                          msg = "null check exception";
                          break;
                      case ABORT_BOUNDS_CODE:
                          name = "BoundsCheckException";
                          msg = "array bounds check exception";
                          break;
                      case ABORT_DIV_CODE:
                          name = "DivideByZeroException";
                          msg = "division by zero";
                          break;
                      case ABORT_ALLOC_CODE:
                          name = "AllocationException";
                          msg = "dynamic memory allocation failed";
                          break;
                      case ABORT_UNIMP_CODE:
                          name = "UnimplementedException";
                          msg = "method not implemented";
                          break;
                  }
                  Terminal.append(Terminal.COLOR_RED, buf, name);
                  buf.append(": ").append(msg).append(" @ ");
                  Terminal.append(Terminal.COLOR_BRIGHT_CYAN, buf, StringUtil.addrToString(pc));
                  printer.printBuffer(buf);
  
                  stack.printStack(printer, sourceMap);
              }
          }
  
          public void report() {
              // do nothing
          }
      }
  
      public VirgilMonitor() {
          super("The \"virgil\" monitor watches for execution of an AVR break " +
                  "instruction, which is used by the Virgil compiler to signal fatal " +
                  "exceptions.");
      }
  
      public Monitor newMonitor(Simulator s) {
          return new Mon(s);
      }
  }
  