threadtest.cc

nachos下的并发程序设计

// threadtest.cc 
//	Simple test case for the threads assignment.
//
//	Create two threads, and have them context switch
//	back and forth between themselves by calling Thread::Yield, 
//	to illustratethe inner workings of the thread system.
//
// Copyright (c) 1992-1993 The Regents of the University of California.
// All rights reserved.  See copyright.h for copyright notice and limitation 
// of liability and disclaimer of warranty provisions.

#include "copyright.h"
#include "system.h"
#include "dllist.h"
// testnum is set in main.cc
int testnum = 1;
extern void ListInsert(int N, DLList *List);
extern void ListRemove(int N, DLList *List);
//--------------------------------------------------------------------i
// SimpleThread
// 	Loop 5 times, yielding the CPU to another ready thread 
//	each iteration.
//
//	"which" is simply a number identifying the thread, for debugging
//	purposes.
//----------------------------------------------------------------------

DLList L;
DLList *List = &L;
void
SimpleThread(int which)
{
    int num;
    int n = 5;
    ListInsert(n,List);
    ListRemove(n,List);
    
   for (num = 0; num < 5; num++) 
   {
	    printf("*** thread %d looped %d times\n", which, num);
        currentThread->Yield();
    }
}

//----------------------------------------------------------------------
// ThreadTest1
// 	Set up a ping-pong between two threads, by forking a thread 
//	to call SimpleThread, and then calling SimpleThread ourselves.
//----------------------------------------------------------------------

void
ThreadTest1()
{
    DEBUG('t', "Entering ThreadTest1");

    Thread *t = new Thread("forked thread");

    t->Fork(SimpleThread, 1);
    SimpleThread(0);
}

//----------------------------------------------------------------------
// ThreadTest
// 	Invoke a test routine.
//----------------------------------------------------------------------

void
ThreadTest()
{
    switch (testnum) {
    case 1:
    case 2:
    case 3:
    case 4:
    case 5:
	        ThreadTest1();
	break;

    default:
	printf("No test specified.\n");

	break;
    }
}