netprocess.java

nachos操作系统框架

package nachos.network;

import nachos.machine.*;
import nachos.threads.*;
import nachos.userprog.*;
import nachos.vm.*;

/**
 * A <tt>VMProcess</tt> that supports networking syscalls.
 */
public class NetProcess extends VMProcess {
    /**
     * Allocate a new process.
     */
    public NetProcess() {
	super();
    }

    private static final int
	syscallConnect = 11,
	syscallAccept = 12;
    
    /**
     * Handle a syscall exception. Called by <tt>handleException()</tt>. The
     * <i>syscall</i> argument identifies which syscall the user executed:
     *
     * <table>
     * <tr><td>syscall#</td><td>syscall prototype</td></tr>
     * <tr><td>11</td><td><tt>int  connect(int host, int port);</tt></td></tr>
     * <tr><td>12</td><td><tt>int  accept(int port);</tt></td></tr>
     * </table>
     * 
     * @param	syscall	the syscall number.
     * @param	a0	the first syscall argument.
     * @param	a1	the second syscall argument.
     * @param	a2	the third syscall argument.
     * @param	a3	the fourth syscall argument.
     * @return	the value to be returned to the user.
     */
    public int handleSyscall(int syscall, int a0, int a1, int a2, int a3) {
	switch (syscall) {
	default:
	    return super.handleSyscall(syscall, a0, a1, a2, a3);
	}
    }
}