Chapter 9, Problem 9.17HW

Explanation of Solution

Perform Next-fit search instead of First-fit search:

In the “Section 9.9.12 (mm.c)”, remove the lines that starts from “/* $begin mmfirstfit */” and ends with “return NULL; /* No fit */”.

Add the following highlighted code to the “Section 9.9.12 (mm.c)”. The modified “mm.c” file is as follows:

/* Global variables */

static char *heap_listp = 0;  /* Pointer to first block */

// Rover for Next fit

static char *rover;

/* Function prototypes for internal helper routines */

static void *extend_heap(size_t words);

heap_listp += (2 * WSIZE);

/* $end mminit */

// Assign heap_listp to rover

rover = heap_listp;

/* $begin mminit */

/* Extend the empty heap with a free block of CHUNKSIZE bytes */

bp = PREV_BLKP(bp);

}

/* $end mmfree */

// If condition to check the rover is not representing the free block

if ((rover > (char *)bp) && (rover < NEXT_BLKP(bp)))

// Assign bp to rover

rover = bp;

/* $begin mmfree */

return bp;

}

{

/* Next fit search instead of first fit search*/

// Assign rover to the character pointer oldrover

char *oldrover = rover;

/* Finding next fit using for loop */

// For loop to search from rover to the end of the list

for (; GET_SIZE(HDRP(rover)) > 0; rover = NEXT_BLKP(rover))

// If condition to check allocation and size of rover

if (!GET_ALLOC(HDRP(rover)) && (asize <= GET_SIZE(HDRP(rover))))

// Return rover

return rover;

// For loop to search from start of list to old rover

for (rover = heap_listp; rover < oldrover; rover = NEXT_BLKP(rover))

// If condition to check allocation and size of rover

if (!GET_ALLOC(HDRP(rover)) && (asize <= GET_SIZE(HDRP(rover))))

// Return rover

return rover;

// Otherwise return null

return NULL;

}

/* $end mmfirstfit */

Filename: main.c

// Include libraries

#include <stdio.h>

#include <stdlib.h>

#include <assert.h>

// Include required header files

#include "csapp...