progtest.cpp

LINUX 下NACHOS 系统的页面调度算法的实现

// progtest.cc 
//      Test routines for demonstrating that Nachos can load
//      a user program and execute it.  
//
//      Also, routines for testing the Console hardware device.
//
// 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 "console.h"
#include "addrspace.h"
#include "synch.h"

//----------------------------------------------------------------------
// StartProcess
//      Run a user program.  Open the executable, load it into
//      memory, and jump to it.
//----------------------------------------------------------------------

void
StartProcess(char *filename)
{
    OpenFile *executable = fileSystem->Open(filename);
    AddrSpace *space;

    if (executable == NULL) {
        printf("Unable to open file %s\n", filename);
        return;
    }
    space = new AddrSpace(executable);    
    currentThread->space = space;

    // delete executable;                       // close file

    space->InitRegisters();             // set the initial register values
    space->RestoreState();              // load page table register

    machine->Run();                     // jump to the user progam
    ASSERT(FALSE);                      // machine->Run never returns;
                                        // the address space exits
                                        // by doing the syscall "exit"
}

// Data structures needed for the console test.  Threads making
// I/O requests wait on a Semaphore to delay until the I/O completes.

static Console *console;
static Semaphore *readAvail;
static Semaphore *writeDone;

//----------------------------------------------------------------------
// ConsoleInterruptHandlers
//      Wake up the thread that requested the I/O.
//----------------------------------------------------------------------

static void ReadAvail(int arg) { readAvail->V(); }
static void WriteDone(int arg) { writeDone->V(); }

//----------------------------------------------------------------------
// ConsoleTest
//      Test the console by echoing characters typed at the input onto
//      the output.  Stop when the user types a 'q'.
//----------------------------------------------------------------------

void 
ConsoleTest (char *in, char *out)
{
    char ch;

    console = new Console(in, out, ReadAvail, WriteDone, 0);
    readAvail = new Semaphore("read avail", 0);
    writeDone = new Semaphore("write done", 0);
    
    for (;;) {
        readAvail->P();         // wait for character to arrive
        ch = console->GetChar();
        console->PutChar(ch);   // echo it!
        writeDone->P() ;        // wait for write to finish
        if (ch == 'q') return;  // if q, quit
    }
}