Universidad de Costa Rica Escuela de Ciencias de la Computación e Informática CI-0122 Sistemas operativos Ejemplos
CI0122 / Ejemplos / 2014-i

// 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 "synch.h"
#include <iostream>
using namespace std;
//----------------------------------------------------------------------
// SimpleThread
// Loop 5 times, yielding the CPU to another ready thread
// each iteration.
//
// "which" is simply a number identifying the thread, for debugging
// purposes.
//----------------------------------------------------------------------

Semaphore c("SemaforoC",0);
Semaphore m("SemaforoM",0);
int ms = 0;
int cs = 0;

void
SimpleThread(int which)
{
   int num;
   if(which == 0){
       cout << "Soy misionero" << endl;
       if(ms >= 1 && cs >= 1){
           m.V();
           c.V();
           ms -= 1;
           cs -= 1;
           cout << "Cruzar!!!" << endl;
           cout<<"misioneros esperando = "<<ms<<endl;
           cout<<"canibales esperando = "<<cs<<endl;
       }else if(ms >= 2){
           m.V();
           m.V();
           ms -= 2;
           cout << "Cruzar!!!" << endl;
           cout<<"misioneros esperando = "<<ms<<endl;
           cout<<"canibales esperando = "<<cs<<endl;
       }else{
           ms++;
           m.P();
       }
   }else{
       cout << "Soy canibal" << endl;
       if(ms >= 2){
           m.V();
           m.V();
           ms -= 2;
           cout << "Cruzar!!!" << endl;
           cout<<"misioneros esperando = "<<ms<<endl;
           cout<<"canibales esperando = "<<cs<<endl;
       }else if(cs >= 2){
           c.V();
           c.V();
           cs -= 2;
           cout << "Cruzar!!!" << endl;
           cout<<"misioneros esperando = "<<ms<<endl;
           cout<<"canibales esperando = "<<cs<<endl;
       }else{
           cs++;
           c.P();
       }
   }
   /*if((ms>=2)&&(cs>=1)){
       ms -= 2;
       cs -= 1;
       s.V();
   }else if (ms>=3){
       ms-=3;
       s.V();
   }else if(cs>=3){
       cs -= 3;
       s.V();
   }else{
       s.P();
       cout << "Cruzar!!!" << endl;
       cout<<"misioneros esperando = "<<ms<<endl;
       cout<<"canibales esperando = "<<cs<<endl;
   }*/
}

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

void
ThreadTest()
{
   int random;
   DEBUG('t', "Entering SimpleTest");
   int i;
   for(i = 1; i < 15; ++i){
       random = Random()%2;
       char name[100];
       sprintf(name,"O %d",random);
       Thread *t = new Thread(name);
       t->Fork(SimpleThread, random);
   }
   SimpleThread(0);
   
}