SimpleRegisterWriteTracker.java

/*
  SimpleRegisterWriteTracker.java

  (c) 2012-2013 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.common.machine;

import java.util.BitSet;
import java.util.Map;
import java.util.TreeMap;


/**
 * Track a series of changes to a set of registers.
 * @author ejs
 *
 */
public class SimpleRegisterWriteTracker extends BaseRegisterWriteTracker {
	private Map<Integer, Integer> changes = new TreeMap<Integer, Integer>(); 
	
	public SimpleRegisterWriteTracker(IRegisterAccess access, int baseReg, BitSet regbits) {
		super(access, baseReg, regbits);
	}

	public SimpleRegisterWriteTracker(IRegisterAccess access) {
		super(access);
	}

	/* (non-Javadoc)
	 * @see v9t9.common.machine.BaseRegisterWriteTracker#clearChanges()
	 */
	@Override
	public void clearChanges() {
		synchronized (changes) {
			changes.clear();
		}
	}

	/* (non-Javadoc)
	 * @see v9t9.common.machine.BaseRegisterWriteTracker#record(int, int)
	 */
	@Override
	protected void record(int reg, int value) {
		synchronized (changes) {
			changes.put(reg, value);
		}
	}
	
	/**
	 * Get the changes, sorted by register key.  Only the last
	 * change to each register is mentioned.
	 * 
	 * Caller may modify
	 * but cannot own the list.
	 * @return the changes
	 */
	public Map<Integer, Integer> getChanges() {
		return changes;
	}
}