SerialConsole.java

// PART OF THE MACHINE SIMULATION. DO NOT CHANGE.

package nachos.machine;

import nachos.security.*;

/**
 * A serial console can be used to send and receive characters. Only one
 * character may be sent at a time, and only one character may be received at a
 * time.
 */

public interface SerialConsole {
    /**
     * Set this console's receive and send interrupt handlers.
     *
     * <p>
     * The receive interrupt handler is called every time another byte arrives
     * and can be read using <tt>readByte()</tt>.
     *
     * <p>
     * The send interrupt handler is called every time a byte sent with
     * <tt>writeByte()</tt> is finished being sent. This means that another
     * byte can be sent.
     *
     * @param	receiveInterruptHandler	the callback to call when a byte
     *					arrives.
     * @param	sendInterruptHandler	the callback to call when another byte
     *					can be sent.
     */
    public void setInterruptHandlers(Runnable receiveInterruptHandler,
                                     Runnable sendInterruptHandler);

    /**
     * Return the next unsigned byte received (in the range <tt>0</tt> through
     * <tt>255</tt>).
     *
     * @return	the next byte read, or -1 if no byte is available.
     */
    public int	readByte();

    /**
     * Send another byte. If a byte is already being sent, the result is not
     * defined.
     *
     * @param	value	the byte to be sent (the upper 24 bits are ignored).
     */
    public void writeByte(int value);
}