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utility.h

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// utility.h 
//      Miscellaneous useful definitions, including debugging routines.
//
//      The debugging routines allow the user to turn on selected
//      debugging messages, controllable from the command line arguments
//      passed to Nachos (-d).  You are encouraged to add your own
//      debugging flags.  The pre-defined debugging flags are:
//
//      '+' -- turn on all debug messages
//      't' -- thread system
//      's' -- semaphores, locks, and conditions
//      'i' -- interrupt emulation
//      'm' -- machine emulation (USER_PROGRAM)
//      'd' -- disk emulation (FILESYS)
//      'f' -- file system (FILESYS)
//      'a' -- address spaces (USER_PROGRAM)
//      'n' -- network emulation (NETWORK)
//
// 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.

#ifndef UTILITY_H
#define UTILITY_H

#include "copyright.h"

// Miscellaneous useful routines

#include <bool.h>
                                                // Boolean values.  
                                                // This is the same definition 
                                                // as in the g++ library.

#define min(a,b)  (((a) < (b)) ? (a) : (b))
#define max(a,b)  (((a) > (b)) ? (a) : (b))

// Divide and either round up or down 
#define divRoundDown(n,s)  ((n) / (s))
#define divRoundUp(n,s)    (((n) / (s)) + ((((n) % (s)) > 0) ? 1 : 0))

// This declares the type "VoidFunctionPtr" to be a "pointer to a
// function taking an integer argument and returning nothing".  With
// such a function pointer (say it is "func"), we can call it like this:
//
//      (*func) (17);
//
// This is used by Thread::Fork and for interrupt handlers, as well
// as a couple of other places.

typedef void (*VoidFunctionPtr)(int arg); 
typedef void (*VoidNoArgFunctionPtr)(); 


// Include interface that isolates us from the host machine system library.
// Requires definition of bool, and VoidFunctionPtr
#include "sysdep.h"                             

// Interface to debugging routines.

extern void DebugInit(char* flags);     // enable printing debug messages

extern bool DebugIsEnabled(char flag);  // Is this debug flag enabled?

extern void DEBUG (char flag, char* format, ...);       // Print debug message 
                                                        // if flag is enabled

//----------------------------------------------------------------------
// ASSERT
//      If condition is false,  print a message and dump core.
//      Useful for documenting assumptions in the code.
//
//      NOTE: needs to be a #define, to be able to print the location 
//      where the error occurred.
//----------------------------------------------------------------------
#define ASSERT(condition)                                                     \
    if (!(condition)) {                                                       \
        fprintf(stderr, "Assertion failed: line %d, file \"%s\"\n",           \
                __LINE__, __FILE__);                                          \
        fflush(stderr);                                                       \
        Abort();                                                              \
    }


#endif UTILITY_H

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