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ref.c
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ref.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define PAGEHIT 0
#define PAGEMISS 1
int * mem;
int mem_size = 0; /* memory size in pages */
/* Your job is to implement the following three functions */
/* input: none */
/* output: page to be replaced */
int fifo()
{
return 0;
}
/***************************************************************/
/* input: none */
/* output: page to be replaced */
int lru()
{
return 0;
}
/***************************************************************/
/* input: none */
/* output: page to be replaced */
int own()
{
return 0;
}
/***************************************************************/
/* Input: file handle
/* Output: non
/* This function writes the memory content to a file */
void print_mem(FILE *file)
{
int i;
for(i = 0; i < mem_size; i++)
fprintf(file, "%d ", mem[i]);
fprintf(file, "\n");
}
/***************************************************************/
/* input: page number */
/* output: NONE */
void insert(int page)
{
unsigned i;
for(i = 0; i < mem_size; i++)
if(!mem[i])
{
mem[i] = page;
return;
}
printf("Memory full and is not suppose to be!!\n");
exit(1);
}
/***************************************************************/
/* Input: page number */
/* Output: page hit or page miss */
int mem_check(int page)
{
unsigned i;
for(i = 0; i < mem_size; i++)
if(mem[i] == page)
return PAGEHIT;
return PAGEMISS;
}
/***************************************************************/
/* Input: none
/* Ouput: 1 if memory is full, 0 otherwise */
int IsFull()
{
unsigned i;
for(i = 0; i < mem_size; i++)
if(!mem[i])
return 0;
return 1;
}
/***************************************************************/
int main(int argc, char * argv[])
{
int policy; /* replacement policy */
int current; /* current page accessed */
FILE * fp; /* The file containing the page accesses */
FILE * rp; /* output file */
char filename[30]={""};
const char * extension[] ={".fifo", ".lru", "new"};
float num_accesses = 0.0; /* total number of page accesses */
float page_faults = 0.0;
unsigned victim = 0; /* page to be replaced */
/* Getting and checking the input from the command line */
if(argc != 4)
{
printf("usage: pager policy size filename\n");
exit(1);
}
policy = atoi(argv[1]);
mem_size = atoi(argv[2]);
if( policy < 0 || policy > 2)
{
printf("policy must be 0, 1, or 2\n");
exit(1);
}
if(mem_size <= 0 )
{
printf("Size must be a positive integer.\n");
exit(1);
}
/* Allocate and initialize the memory */
mem = (int *)calloc(mem_size, sizeof(int));
if(!mem)
{
printf("Cannot allocate mem\n");
exit(1);
}
/* open the memory access file */
fp = fopen(argv[3], "r");
if(!fp)
{
printf("Cannot open file %s\n", argv[3]);
exit(1);
}
/* Create the output file */
strcat(filename, argv[3]);
strcat(filename,extension[policy]);
rp = fopen(filename, "w");
if(!rp)
{
printf("Cannot create file %s\n", filename);
exit(1);
}
/* The main loop of the program */
fscanf(fp,"%d", ¤t);
while(!feof(fp))
{
num_accesses++;
if(mem_check(current) == PAGEMISS)
page_faults++;
switch(policy)
{
case 0: if( IsFull())
{
victim = fifo();
mem[victim] = current;
}
else
insert(current);
break;
case 1: if( IsFull())
{
victim = lru();
mem[victim] = current;
}
else
insert(current);
break;
case 2: if( IsFull())
{
victim = own();
mem[victim] = current;
}
else
insert(current);
break;
default: printf("Unknown policy ... Exiting\n");
exit(1);
}/* end switch-case */
print_mem(rp);
fscanf(fp,"%d", ¤t);
}/* end while */
fprintf(rp,"percentage of page faults = %f", page_faults/num_accesses);
/* wrap-up */
fclose(fp);
fclose(rp);
free(mem);
return 1;
}