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update

homework4
邓博昊 10 months ago
parent
abc49ae458
commit
cc75799cf6
3 changed files with 355 additions and 26 deletions
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  1. BIN
      mdriver
  2. +355
    -26
      mm.c
  3. BIN
      mm.o

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mdriver View File


+ 355
- 26
mm.c View File

@ -44,61 +44,390 @@ team_t team = {
#define SIZE_T_SIZE (ALIGN(sizeof(size_t))) #define SIZE_T_SIZE (ALIGN(sizeof(size_t)))
/* Basic constants and macros */
#define WSIZE 4 /* Word and header/footer size (bytes) */
#define DSIZE 8 /* Double word size (bytes) */
#define CHUNKSIZE (1<<12) /* Extend heap by this amount (bytes) */
#define MAX(x, y) ((x) > (y) ? (x) : (y))
/* Pack a size and allocated bit into word */
#define PACK(size, alloc) ((size) | (alloc))
/* Read and write a word at address p */
#define GET(p) (*(unsigned int *)(p))
#define PUT(p, val) (*(unsigned int *)(p) = (val))
/* Read and write a pointer at address p */
#define GET_PTR(p) ((unsigned int *)(long)(GET(p)))
#define PUT_PTR(p, ptr) (*(unsigned int *)(p) = ((long)ptr))
/* Read the size and allocated fields from address p */
#define GET_SIZE(p) (GET(p) & ~0x7)
#define GET_ALLOC(p) (GET(p) & 0x1)
/* Given block ptr bp, compute address of its header and footer */
#define HDRP(bp) ((char *)(bp) - WSIZE)
#define FTRP(bp) ((char *)(bp) + GET_SIZE(HDRP(bp)) - DSIZE)
/* Given block ptr bp, compute address of next and previous blocks */
#define NEXT_BLKP(bp) ((char *)(bp) + GET_SIZE(((char *)(bp) - WSIZE)))
#define PREV_BLKP(bp) ((char *)(bp) - GET_SIZE(((char *)(bp) - DSIZE)))
/* 每个free list中块的大小范围 */
#define SIZE1 (1<<4)
#define SIZE2 (1<<5)
#define SIZE3 (1<<6)
#define SIZE4 (1<<7)
#define SIZE5 (1<<8)
#define SIZE6 (1<<9)
#define SIZE7 (1<<10) /* 1 KB */
#define SIZE8 (1<<11)
#define SIZE9 (1<<12)
#define SIZE10 (1<<13)
#define SIZE11 (1<<14)
#define SIZE12 (1<<15)
#define SIZE13 (1<<16)
#define SIZE14 (1<<17)
#define SIZE15 (1<<18)
#define SIZE16 (1<<19)
#define SIZE17 (1<<20) /* 1 MB */
#define LISTS_NUM 18 /* free list 的数量 */
/* Globe var */
static char *heap_listp;
/* 函数声明 */
static void *extend_heap(size_t words);
static void *coalesce(void *bp);
static void *find_fit(size_t asize);
static void place(void *bp, size_t asize);
static void insert_list(void *bp);
int getListOffset(size_t size);
void delete_list(void *bp);
/* /*
* mm_init - initialize the malloc package. * mm_init - initialize the malloc package.
*/ */
int mm_init(void) int mm_init(void)
{ {
return 0;
char *bp;
int i;
if ((heap_listp = mem_sbrk((LISTS_NUM + 4) * WSIZE)) == (void *)-1) {
return -1;
}
PUT(heap_listp + LISTS_NUM * WSIZE, 0);
PUT(heap_listp + (1 + LISTS_NUM) * WSIZE, PACK(DSIZE, 1));
PUT(heap_listp + (2 + LISTS_NUM) * WSIZE, PACK(DSIZE, 1));
PUT(heap_listp + (3 + LISTS_NUM) * WSIZE, PACK(0, 1));
for (i = 0; i < LISTS_NUM; i++) {
PUT_PTR(heap_listp + WSIZE * i, NULL);
}
/* Extend the empty heap with a free block of CHUNKSIZE bytes */
if ((bp = extend_heap(CHUNKSIZE / WSIZE)) == NULL) {
return -1;
}
return 0;
}
/*
* 扩展heap的大小
*/
void *extend_heap(size_t words)
{
char *bp;
size_t size;
/* Allocate an even number of words to maintain alignment */
size = (words % 2) ? ((words + 1) * WSIZE) : (words * WSIZE);
if ((long)(bp = mem_sbrk(size)) == -1) {
return NULL;
}
/* Initialize free block header/footer and the epilogue header */
PUT(HDRP(bp), PACK(size, 0)); /* Free block header */
PUT(FTRP(bp), PACK(size, 0)); /* Free block footer */
PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); /* New epilogue header */
/* Coalesce if the previous block was free */
return coalesce(bp);
}
/*
* 合并free block
*/
void *coalesce(void *bp)
{
size_t prev_alloc = GET_ALLOC(FTRP(PREV_BLKP(bp)));
size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp)));
size_t size = GET_SIZE(HDRP(bp));
if (prev_alloc && next_alloc) { /* 前后都分配了 */
bp = bp;
} else if (prev_alloc && !next_alloc) { /* 前分配, 后未分配 */
delete_list(NEXT_BLKP(bp));
size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
PUT(HDRP(bp), PACK(size, 0));
PUT(FTRP(bp), PACK(size, 0));
} else if (!prev_alloc && next_alloc) { /* 前未分配, 后分配 */
delete_list(PREV_BLKP(bp));
size += GET_SIZE(HDRP(PREV_BLKP(bp)));
PUT(FTRP(bp), PACK(size, 0));
PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
bp = PREV_BLKP(bp);
} else { /* 前后都未分配 */
delete_list(NEXT_BLKP(bp));
delete_list(PREV_BLKP(bp));
size = size + GET_SIZE(HDRP(PREV_BLKP(bp))) +
GET_SIZE(HDRP(NEXT_BLKP(bp)));
PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
PUT(FTRP(NEXT_BLKP(bp)), PACK(size, 0));
bp = PREV_BLKP(bp);
}
insert_list(bp);
return bp;
} }
/* /*
* mm_malloc - Allocate a block by incrementing the brk pointer.
* Always allocate a block whose size is a multiple of the alignment.
* mm_malloc - Allocate a block by searching the free list.
* Always allocate a block whose size is a multiple of the alignment.
*/ */
void *mm_malloc(size_t size) void *mm_malloc(size_t size)
{
size_t asize; /* Adjusted block size */
size_t extendsize; /* Amount to extend heap if no fit */
char *bp;
/* Igore spurious requests */
if (0 == size) {
return NULL;
}
/* Adjusted block size to include overhead and alignment reqs */
if (size <= DSIZE) {
asize = 2 * DSIZE;
} else {
asize = DSIZE * ((size + (DSIZE) + (DSIZE - 1)) / DSIZE);
}
/* Search the free list for a fit */
if ((bp = find_fit(asize)) != NULL) {
place(bp, asize);
return bp;
}
/* No fit found. Get more memory and place the block */
extendsize = MAX(asize, CHUNKSIZE);
if ((bp = extend_heap(extendsize / WSIZE)) == NULL) {
return NULL;
}
place(bp, asize);
return bp;
}
/*
* getListOffset - 得到大小为size的块应该在哪个list中
*/
int getListOffset(size_t size)
{
if (size <= SIZE1) {
return 0;
} else if (size <= SIZE2) {
return 1;
} else if (size <= SIZE3) {
return 2;
} else if (size <= SIZE4) {
return 3;
} else if (size <= SIZE5) {
return 4;
} else if (size <= SIZE6) {
return 5;
} else if (size <= SIZE7) {
return 6;
} else if (size <= SIZE8) {
return 7;
} else if (size <= SIZE9) {
return 8;
} else if (size <= SIZE10) {
return 9;
} else if (size <= SIZE11) {
return 10;
} else if (size <= SIZE12) {
return 11;
} else if (size <= SIZE13) {
return 12;
} else if (size <= SIZE14) {
return 13;
} else if (size <= SIZE15) {
return 14;
} else if (size <= SIZE16) {
return 15;
} else if (size <= SIZE17) {
return 16;
} else {
return 17;
}
}
/*
* insert_list - 将free block插入到相应大小的free list中, 插入位置为表头
*/
void insert_list(void *bp)
{
int index;
size_t size;
size = GET_SIZE(HDRP(bp));
index = getListOffset(size);
if (GET_PTR(heap_listp + WSIZE * index) == NULL) {
PUT_PTR(heap_listp + WSIZE * index, bp);
PUT_PTR(bp, NULL);
PUT_PTR((unsigned int *)bp + 1, NULL);
} else {
PUT_PTR(bp, GET_PTR(heap_listp + WSIZE * index));
PUT_PTR(GET_PTR(heap_listp + WSIZE * index) + 1, bp); /* 修改前一个位置 */
PUT_PTR((unsigned int *)bp + 1, NULL);
PUT_PTR(heap_listp + WSIZE * index, bp);
}
}
/*
* delete_list - 删除链表结点
*/
void delete_list(void *bp)
{
int index;
size_t size;
size = GET_SIZE(HDRP(bp));
index = getListOffset(size);
if (GET_PTR(bp) == NULL && GET_PTR((unsigned int *)bp + 1) == NULL) {
/* 链表中唯一结点 */
PUT_PTR(heap_listp + WSIZE * index, NULL);
} else if (GET_PTR(bp) == NULL && GET_PTR((unsigned int *)bp + 1) != NULL) {
/* 链表中最后一个结点, 不是唯一一个 */
PUT_PTR(GET_PTR((unsigned int *)bp + 1), NULL);
} else if (GET_PTR(bp) != NULL && GET_PTR((unsigned int *)bp + 1) == NULL){
/* 链表中第一个结点, 不是唯一一个 */
PUT_PTR(heap_listp + WSIZE * index, GET_PTR(bp));
PUT_PTR(GET_PTR(bp) + 1, NULL);
} else if (GET_PTR(bp) != NULL && GET_PTR((unsigned int *)bp + 1) != NULL) {
/* 链表中的中间结点 */
PUT_PTR(GET_PTR((unsigned int *)bp + 1), GET_PTR(bp));
PUT_PTR(GET_PTR(bp) + 1, GET_PTR((unsigned int*)bp + 1));
}
}
/*
* find_fit - Search the free list for a fit
*/
void *find_fit(size_t asize)
{ {
int newsize = ALIGN(size + SIZE_T_SIZE);
void *p = mem_sbrk(newsize);
if (p == (void *)-1)
int index;
index = getListOffset(asize);
unsigned int *ptr;
/* 小的class内找不到就到大的class内找 */
while (index < 18) {
ptr = GET_PTR(heap_listp + 4 * index);
while (ptr != NULL) {
if (GET_SIZE(HDRP(ptr)) >= asize) {
return (void *)ptr;
}
ptr = GET_PTR(ptr);
}
index++;
}
return NULL; return NULL;
else {
*(size_t *)p = size;
return (void *)((char *)p + SIZE_T_SIZE);
}
} }
/* /*
* mm_free - Freeing a block does nothing.
* place - place the requested block at the beginning of the free block
*/
void place(void *bp, size_t asize)
{
size_t csize = GET_SIZE(HDRP(bp));
delete_list(bp);
if ((csize - asize) >= (2 * DSIZE)) {
PUT(HDRP(bp), PACK(asize, 1));
PUT(FTRP(bp), PACK(asize, 1));
bp = NEXT_BLKP(bp);
PUT(HDRP(bp), PACK(csize - asize, 0));
PUT(FTRP(bp), PACK(csize - asize, 0));
insert_list(bp);
} else {
PUT(HDRP(bp), PACK(csize, 1));
PUT(FTRP(bp), PACK(csize, 1));
}
}
/*
* mm_free - Freeing a block.
*/ */
void mm_free(void *ptr) void mm_free(void *ptr)
{ {
size_t size = GET_SIZE(HDRP(ptr));
PUT(HDRP(ptr), PACK(size, 0));
PUT(FTRP(ptr), PACK(size, 0));
coalesce(ptr);
} }
/* /*
* mm_realloc - Implemented simply in terms of mm_malloc and mm_free
* mm_realloc - 直接用malloc和free组合实现
*/ */
void *mm_realloc(void *ptr, size_t size) void *mm_realloc(void *ptr, size_t size)
{ {
void *oldptr = ptr;
void *newptr;
size_t copySize;
newptr = mm_malloc(size);
if (newptr == NULL)
return NULL;
copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
if (size < copySize)
copySize = size;
memcpy(newptr, oldptr, copySize);
mm_free(oldptr);
return newptr;
}
size_t asize;
void *oldptr = ptr;
void *newptr;
/* free */
if (0 == size) {
free(oldptr);
return NULL;
}
if (size <= DSIZE) {
asize = 2 * DSIZE;
} else {
asize = DSIZE * ((size + (DSIZE) + (DSIZE - 1)) / DSIZE);
}
if (asize == GET_SIZE(HDRP(oldptr))) {
return oldptr;
}
/* 缩小空间 */
if (asize < GET_SIZE(HDRP(oldptr))) {
newptr = mm_malloc(size);
memmove(newptr, oldptr, size);
mm_free(oldptr);
return newptr;
}
newptr = mm_malloc(size);
if (NULL == newptr)
return NULL;
memmove(newptr, oldptr, size);
mm_free(oldptr);
return newptr;
}

BIN
mm.o View File


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