*
* written by Vangelis Rokas, 2004 (vrokas@otenet.gr)
*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * In other words, you are welcome to use, share and improve this program.
+ * You are forbidden to forbid anyone else to use, share and improve
+ * what you give them. Help stamp out software-hoarding!
+ *
+ * $Id$
*/
-#include "malloc.h"
+#include <malloc.h>
-extern unsigned char _MALLOC_SPEC *_dynamicHeap; /* pointer to heap */
+/* this is an external pointer to HEAP. It should be defined in
+ * the user's program, or it can be a symbol created by linker */
+extern unsigned char _MALLOC_SPEC *heap;
unsigned char _MALLOC_SPEC *malloc(unsigned char len)
{
_malloc_rec _MALLOC_SPEC *pHeap; /* pointer to block header */
_malloc_rec _MALLOC_SPEC *temp;
- unsigned char bLen; /* size of block */
- unsigned char eLen;
+ unsigned char bLen, eLen; /* size of block */
+#if MALLOC_MAX_FIRST
+ unsigned char pass=1;
+#endif
+
+ if(len >= MAX_BLOCK_SIZE)
+ goto do_end;
+
+ pHeap = (_malloc_rec _MALLOC_SPEC *)&heap;
+
+ while(1) {
+ bLen = pHeap->bits.count;
+
+ /* if datum is zero, then last block, return NULL */
+ if(pHeap->datum == 0) {
+#if !MALLOC_MAX_FIRST
+ goto do_end;
+#else
+ if(!pass)
+ goto do_end;
+
+ /* in the first pass, we search for blocks that have
+ * the requested size, in the second pass, try to merge
+ * adjacent blocks to 'make' the requested block */
+ pHeap = (_malloc_rec _MALLOC_SPEC *)&heap;
+ pass--;
+ continue;
+#endif
+ }
+
+ /* if current block is allocated then proceed to next */
+ if(pHeap->bits.alloc)
+ goto do_continue;
- if(len > _MAX_HEAP_SIZE)
- return ((unsigned char _MALLOC_SPEC *)0);
+
+ /* current block is not allocated, try to allocate */
+
+ /* if current block is not enough for allocation, then proceed to next */
+ if(bLen <= len) {
- pHeap = (_malloc_rec _MALLOC_SPEC *)&_dynamicHeap;
+#if MALLOC_MAX_FIRST
+ /* if we are in the first pass, check next block */
+ if(pass)
+ goto do_continue;
+ /* otherwise try merge */
+#endif
- while(1) {
- bLen = pHeap->bits.count;
-
- /* if datum is zero, then last block, return NULL */
- if(pHeap->datum == 0)
- return ((unsigned char _MALLOC_SPEC *)0);
+ temp = _mergeHeapBlock(pHeap, len);
+
+ if(!temp)
+ /* otherwise proceed with next block */
+ goto do_continue;
- /* if current block is allocated then proceed to next */
- if(pHeap->bits.alloc) {
- pHeap += pHeap->bits.count;
- continue;
- }
+ pHeap = temp;
+ bLen = pHeap->bits.count;
+ }
+
+ /* current block is enough to hold the new block */
+
+ /* allocate by filling the fields */
+ eLen = (len+1);
+ pHeap->datum = 0x80 | eLen;
+
+ if(bLen > eLen) {
+ /* if current block size is greater than the requested one,
+ * create a new empty block at the end of the newly allocated */
+ temp = (_malloc_rec _MALLOC_SPEC *)((unsigned int)pHeap + eLen);
+ temp->datum = (bLen - eLen);
+ }
+
+ return ((unsigned char _MALLOC_SPEC *)((unsigned int)pHeap + 1));
+
+do_continue:
+ pHeap = (_malloc_rec _MALLOC_SPEC *)((unsigned int)pHeap + bLen);
+ //pHeap->bits.count);
+ }
+
+do_end:
+ return ((unsigned char _MALLOC_SPEC *)0);
-
- /* current block is not allocated, try to allocate */
-
- /* if current block is not enough for allocation, then proceed to next */
- if(bLen <= len) {
-
- /* current block is not enough see if we can merge some adjacent
- * memory blocks to make it fit */
- temp = pHeap + pHeap->bits.count;
- eLen = bLen;
- while((temp->datum) && (!temp->bits.alloc) && (eLen < len)) {
- eLen += temp->bits.count;
- temp += temp->bits.count;
- }
-
- if(eLen >= len) {
- int i;
- /* yes, there are some free blocks that can be merged, merge them... */
-
- temp = pHeap;
- while(eLen > 0) {
- if(eLen > MAX_BLOCK_SIZE)i = MAX_BLOCK_SIZE;
- else i = eLen;
-
- temp->bits.count = i;
- temp->bits.alloc = 0;
-
- temp += i;
- eLen -= i;
- }
-
- bLen = pHeap->bits.count;
- } else {
- /* otherwise proceed with next block */
- pHeap += pHeap->bits.count;
- continue;
- }
- }
-
-
- /* current block is enough to hold the new block */
-
- /* allocate by filling the fields */
- pHeap->bits.count = len+1;
- pHeap->bits.alloc = 1;
-
- if(bLen > len+1) {
- /* if current block size is greater than the requested one,
- * create a new empty block at the end of the newly allocated */
- temp = pHeap + len+1;
- temp->bits.count = bLen - len - 1;
- temp->bits.alloc = 0;
- }
-
- return ((unsigned char _MALLOC_SPEC *)pHeap + 1);
- }
}
projects / fw / sdcc / blobdiff