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Changed the way, used blocks are managed

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git-svn-id: svn://svn.cc65.org/cc65/trunk@3340 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2004-12-19 23:09:38 +00:00
parent 49d1a47269
commit e55a4bcfd4
5 changed files with 83 additions and 41 deletions
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13
asminc/_heap.inc
View file

@ -13,12 +13,19 @@
; probably not work.
.struct freeblock
size .word
next .word
prev .word
next .addr
prev .addr
.endstruct
; Struct usedblock
; See notes above
.struct usedblock
size .word
start .addr
.endstruct
HEAP_ADMIN_SPACE = 2
HEAP_MIN_BLOCKSIZE = .sizeof (freeblock) ; Minimum size of an allocated block
HEAP_ADMIN_SPACE = .sizeof (usedblock) ; Additional space for used bocks
; Variables
.global __heaporg

16
include/_heap.h
View file

@ -1,7 +1,7 @@
/*
* _heap.h
*
* Ullrich von Bassewitz, 03.06.1998
* Ullrich von Bassewitz, 1998-06-03, 2004-12-19
*
*/
@ -12,12 +12,22 @@
/* Structure that preceeds a user block in most cases.
* The aligned_malloc function may generate blocks where the start pointer
* and size are splitted to handle a memory hole that is needed for
* alignment.
*/
struct usedblock {
unsigned size;
struct usedblock* start;
};
/* Space needed for administering used blocks */
#define HEAP_ADMIN_SPACE sizeof (unsigned)
#define HEAP_ADMIN_SPACE sizeof (struct usedblock)
/* The data type used to implement the free list.
* Beware: Field order is significant!
*/
*/
struct freeblock {
unsigned size;
struct freeblock* next;

28
libsrc/common/free.s
View file

@ -72,23 +72,32 @@
_free: sta ptr2
stx ptr2+1 ; Save block
; Is the argument NULL?
; Is the argument NULL? If so, bail out.
ora ptr2+1 ; Is the argument NULL?
beq @L9 ; Jump if yes
bne @L0 ; Jump if no
rts ; Bail out if yes
; Decrement the given pointer by the admin space amount, so it points to the
; real block allocated. The size of the block is stored in the admin space.
; There's a pointer below the user space that points to the real start of the
; raw block. The first word of the raw block is the total size of the block.
; Remember the block size in ptr1.
lda ptr2
sub #HEAP_ADMIN_SPACE
@L0: lda ptr2
sub #2
sta ptr2
bcs @L1
dec ptr2+1
@L1: ldy #freeblock::size+1
@L1: ldy #1
lda (ptr2),y ; High byte of real block address
tax
dey
lda (ptr2),y
stx ptr2+1
sta ptr2 ; Set ptr2 to start of real block
ldy #usedblock::size+1
lda (ptr2),y ; High byte of size
sta ptr1+1 ; Save it
sta ptr1+1 ; Save it
dey
lda (ptr2),y
sta ptr1
@ -261,7 +270,7 @@ _free: sta ptr2
; }
; } else {
; f->prev = 0;
; /* Special case: This is the new freelist start */
; /* Special case: This is the new freelist start */
; _hfirst = f;
; }
; }
@ -530,3 +539,4 @@ NoLeftMerge:

18
libsrc/common/malloc.s
View file

@ -309,17 +309,27 @@ SliceBlock:
stx ptr2
sta ptr2+1
; Fill the size into the admin space of the block and return the user pointer
; Fill the size and start address into the admin space of the block
; (struct usedblock) and return the user pointer
FillSizeAndRet:
ldy #freeblock::size ; *p = size;
lda ptr1 ; Low byte of block size
ldy #usedblock::size ; p->size = size;
lda ptr1 ; Low byte of block size
sta (ptr2),y
iny ; Points to freeblock::size+1
iny ; Points to freeblock::size+1
lda ptr1+1
sta (ptr2),y
RetUserPtr:
ldy #usedblock::start ; p->start = p
lda ptr2
sta (ptr2),y
iny
lda ptr2+1
sta (ptr2),y
; Return the user pointer, which points behind the struct usedblock
lda ptr2 ; return ++p;
ldx ptr2+1
add #HEAP_ADMIN_SPACE

49
libsrc/common/realloc.c
View file

@ -6,7 +6,7 @@
/* */
/* */
/* */
/* (C) 1998-2002 Ullrich von Bassewitz */
/* (C) 1998-2004 Ullrich von Bassewitz */
/* Wacholderweg 14 */
/* D-70597 Stuttgart */
/* EMail: uz@musoftware.de */
@ -41,9 +41,10 @@
void* __fastcall__ realloc (void* block, size_t size)
{
unsigned* b;
unsigned* newblock;
struct usedblock* b;
struct usedblock* newblock;
unsigned oldsize;
unsigned newhptr;
int diff;
/* Check the block parameter */
@ -56,7 +57,7 @@ void* __fastcall__ realloc (void* block, size_t size)
if (size == 0) {
/* Block is not NULL, but size is: free the block */
free (block);
return 0;
return 0;
}
/* Make the internal used size from the given size */
@ -65,22 +66,26 @@ void* __fastcall__ realloc (void* block, size_t size)
size = sizeof (struct freeblock);
}
/* Get a pointer to the real block, get the old block size */
b = (unsigned*) (((int) block) - 2);
oldsize = *b;
/* The word below the user block contains a pointer to the start of the
* raw memory block. The first word of this raw memory block is the full
* size of the block. Get a pointer to the real block, get the old block
* size.
*/
b = (((struct usedblock*) block) - 1)->start;
oldsize = b->size;
/* Get the size difference as a signed quantity */
diff = size - oldsize;
/* Is the block at the current heap top? */
if (((int) b) + oldsize == ((int) _heapptr)) {
if (((unsigned) b) + oldsize == ((unsigned) _heapptr)) {
/* Check if we've enough memory at the heap top */
int newhptr;
newhptr = ((int) _heapptr) + diff;
if (newhptr <= ((int) _heapend)) {
newhptr = ((unsigned) _heapptr) + diff;
if (newhptr <= ((unsigned) _heapend)) {
/* Ok, there's space enough */
_heapptr = (unsigned*) newhptr;
*b = size;
b->size = size;
b->start = b;
return block;
}
}
@ -90,17 +95,17 @@ void* __fastcall__ realloc (void* block, size_t size)
*/
if (newblock = malloc (size)) {
/* Adjust the old size to the user visible portion */
oldsize -= sizeof (unsigned);
/* Adjust the old size to the user visible portion */
oldsize -= HEAP_ADMIN_SPACE;
/* If the new block is larger than the old one, copy the old
* data only
*/
if (size > oldsize) {
size = oldsize;
}
/* If the new block is larger than the old one, copy the old
* data only
*/
if (size > oldsize) {
size = oldsize;
}
/* Copy the block data */
/* Copy the block data */
memcpy (newblock, block, size);
free (block);
}
@ -109,4 +114,4 @@ void* __fastcall__ realloc (void* block, size_t size)