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.arch.legacy.LegacyInstr;
  import avrora.core.Program;
  import avrora.sim.State;
  
  /**
   * The <code>MemoryMatrixProfiler</code> class collects information about a program's usage of memory. For
   * each instruction in the program, it tracks the memory locations read and written by that instruction. For
   * example, a load instruction that uses an address in a register might load bytes from various locations in
   * the data memory. This class maintains two internal two-dimensional matrices, one for read counts and one
   * for write counts. The matrices are indexed by code address and data address.
   *
   * @author Ben L. Titzer
   */
  public class MemoryMatrixProfiler {
  
      /**
       * The <code>rcount</code> field stores a two dimensional array that records the read count for each
       * memory location for each instruction. It is indexed by program address, and then by data address. This
       * matrix is row-sparse in that rows of all zero (e.g. a non-memory instruction) are not stored. To access
       * this matrix, use the <code>getReadCount()</code> method.
       */
      public final long[][] rcount;
  
      /**
       * The <code>rcount</code> field stores a two dimensional array that records the write count for each
       * memory location for each instruction. It is indexed by program address, and then by data address. This
       * matrix is row-sparse in that rows of all zero (e.g. a non-memory instruction) are not stored. To access
       * this matrix, use the <code>getWriteCount()</code> method.
       */
      public final long[][] wcount;
  
      /**
       * The <code>ramSize</code> field stores the maximum RAM address that should be recorded.
       */
      public final int ramSize;
  
      /**
       * The constructor for the <code>MemoryMatrixProfiler</code> class creates a new memory probe that can be
       * inserted into the simulator to record the full memory access statistics of the program.
       *
       * @param p    the program to record statistics for
       * @param size the size of the RAM in bytes
       */
      public MemoryMatrixProfiler(Program p, int size) {
          ramSize = size;
          rcount = new long[p.program_end][];
          wcount = new long[p.program_end][];
      }
  
      /**
       * The <code>fireBeforeRead()</code> method is called before the data address is read by the program. In
       * the implementation of <code>MemoryMatrixProfiler</code>, it simply increments the count of reads at the
       * address of the instruction and memory location by one.
       *
       * @param i         the instruction being probed
       * @param address   the address at which this instruction resides
       * @param state     the state of the simulation
       * @param data_addr the address of the data being referenced
       * @param value     the value of the memory location being read
       */
      public void fireBeforeRead(LegacyInstr i, int address, State state, int data_addr, byte value) {
          if (data_addr < ramSize) {
              if (rcount[address] == null) rcount[address] = new long[ramSize];
              rcount[address][data_addr]++;
          }
      }
  
      /**
       * The <code>fireBeforeWrite()</code> method is called before the data address is written by the program.
       * In the implementation of <code>MemoryMatrixProfiler</code>, it simply increments the count of writes at
       * the address of the instruction and memory location by one.
       *
       * @param i         the instruction being probed
       * @param address   the address at which this instruction resides
       * @param state     the state of the simulation
       * @param data_addr the address of the data being referenced
       * @param value     the value being written to the memory location
       */
      public void fireBeforeWrite(LegacyInstr i, int address, State state, int data_addr, byte value) {
          if (data_addr < ramSize) {
              if (wcount[address] == null) wcount[address] = new long[ramSize];
              wcount[address][data_addr]++;
          }
      }
  
      /**
       * The <code>fireAfterRead()</code> method is called after the data address is read by the program. In the
       * implementation of <code>MemoryMatrixProfiler</code>, it does nothing.
       *
       * @param i         the instruction being probed
       * @param address   the address at which this instruction resides
       * @param state     the state of the simulation
       * @param data_addr the address of the data being referenced
       * @param value     the value of the memory location being read
       */
      public void fireAfterRead(LegacyInstr i, int address, State state, int data_addr, byte value) {
          // do nothing
      }
  
      /**
       * The <code>fireAfterWrite()</code> method is called after the data address is written by the program. In
       * the implementation of <code>MemoryMatrixProfiler</code>, it does nothing.
       *
       * @param i         the instruction being probed
       * @param address   the address at which this instruction resides
       * @param state     the state of the simulation
       * @param data_addr the address of the data being referenced
       * @param value     the value being written to the memory location
       */
      public void fireAfterWrite(LegacyInstr i, int address, State state, int data_addr, byte value) {
          // do nothing
      }
  
      /**
       * The <code>getReadCount()</code> method returns the number of times the specified instruction read the
       * specified memory address.
       *
       * @param address   the program address of the instruction
       * @param data_addr the address of the byte of memory
       * @return the number of times the specified instruction read the specified memory address.
       */
      public long getReadCount(int address, int data_addr) {
          return getCount(rcount, data_addr, address);
      }
  
      /**
       * The <code>getWriteCount()</code> method returns the number of times the specified instruction wrote the
       * specified memory address.
       *
       * @param address   the program address of the instruction
       * @param data_addr the address of the byte of memory
       * @return the number of times the specified instruction wrote the specified memory address.
       */
      public long getWriteCount(int address, int data_addr) {
          return getCount(wcount, data_addr, address);
      }
  
      private long getCount(long[][] matrix, int data_addr, int address) {
          if (data_addr < ramSize)
              if (matrix[address] == null)
                  return 0;
              else
                  return matrix[address][data_addr];
          return 0;
      }
  
  }
  