pageOffset_skeleton.c

/**
 * Program that masks page number and offset from an
 * unsigned 32-bit address.
 * The size of a page is 4 KB = 4096 Bytes(4096 = 2^12 and so n = 12 bits)
 * A memory reference appears as:
 * |-----------|-----|
 *  31     12 11     0
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#define PAGE_NUMBER_MASK 0xFFFFF000
#define OFFSET_MASK 0x00000FFF
#define SHIFT 12

int main(int argc, char *argv[]) {
	if(argc != 2 )
	{
		fprintf(stderr, "Usage: ./a.out <virtual address>\n");
		return -1;
	}

	int page_num, offset;
	unsigned int reference;

	reference = (unsigned int)atoi(argv[1]);
	printf("The address %d contains:\n",reference);

	//  mask the page number 
	page_num = (reference & PAGE_NUMBER_MASK) >> SHIFT;
	offset = reference & OFFSET_MASK;
	printf("page number = %d\n", page_num);
	printf("offset = %d\n", offset);


	printf("page number = %d\n",page_num);
	printf("offset = %d\n",offset);

	return 0;
}