package duckMachine.architecture;

/**
 *  The memory unit of the machine. 
 *  @author Amr Sabry
 *  @version jdk-1.1
 */

public class Memory implements MemoryI {
  private Word[] memoryCells;
  private int size;

  public Memory () { this(DEFAULT_SIZE); }

  public Memory (int s) {
     size = s;
     memoryCells = new Word[s];
     for (int i=0; i<s; i++) 
      memoryCells[i] = new Data(0);
   }

   public int getSize() { return size; }

  /**
   * Returns the contents of a specified address.
   * @param addr The address.
   * @see Word
   * @exception MemoryE If the address is out of range.
   */
   public Word fetch (Word addr) throws MemoryE { 
    int intaddr = addr.toInt();
    try { return memoryCells[intaddr]; }
    catch (ArrayIndexOutOfBoundsException e) {
      throw new MemoryE(intaddr);
    }
  }

  /**
   * Stores a word in a specified address.
   * @param addr The address.
   * @param word The object to store in the address.
   * @see Word
   * @exception MemoryE If the address is out of range.
   */
  public void store (Word addr, Word word) throws MemoryE { 
      int intaddr = addr.toInt();
      try { memoryCells[intaddr] = word; }
      catch (ArrayIndexOutOfBoundsException e) {
        throw new MemoryE(intaddr);
      }
  }


}