simulatoredgedlatch.java~

Java遗传算法库

/*
 * SimulatorEdgeDLatch.java
 *
 * Created on 17 July 2003, 13:47
 */

package es.pj.circuits.fpgaft;

/**
 *
 * @author  mmg20
 */
public class SimulatorEdgeDLatch extends SimulatorFaultyDelayLE {
    // Constants
    /** Index of Clock in inputs array */
    public static final int C = 0;
    /** Index of Data in inputs array */
    public static final int D = 1;
    
    // Working vars
    protected boolean prevC = true; // Start un-triggered
    protected boolean prevD = false;
    
    /** Creates a new instance of SimulatorEdgeDLatch */
    public SimulatorEdgeDLatch( int delay ) {
        super( delay );
    }
    
    public final void sampleInputs()
    {
        boolean evValue = evaluateNow();
        boolean changing = currentOutput ^ nextOutput;
                
        if( ( changing && ( evValue != nextOutput ) ) || ( !changing && ( evValue != currentOutput ) ) )
        {
            nextOutput = evValue;
            delayLeft = delay;
            changing = true;
        }
    }
    
    protected final boolean evaluateNow()
    {
        boolean rv;
        boolean currC = inputs[ C ].getNow();
        boolean risingEdge = !prevC && currC;
        if( risingEdge )
        {
            rv = prevD;
        }else
        {
            rv = nextOutput;
        }
        prevC = currC;
        prevD = inputs[ D ].getNow(); // could do only when triggered (IE currC = 0)
        
        return rv;
    }
    
    public String toString()
    {
        String rv = "Edge Triggered D-Latch with delay = " + delay;
        return rv;
    }
    
}