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/**************************************************************************
*
* Copyright (c) 2013 Alcatel-Lucent
*
* Alcatel Lucent licenses this file to You under the Apache License,
* Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. A copy of the License is contained the
* file LICENSE at the top level of this repository.
* You may also obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
**************************************************************************
*
* sbrk.c:
*
* Used by malloc to get memory from "somewhere".
*
* Original author: Ed Sutter (ed.sutter@alcatel-lucent.com)
*
*/
#include "config.h"
#if INCLUDE_MALLOC
#include "genlib.h"
#define NULL 0
extern int releaseExtendedHeap(int);
static long allocbuf[ALLOCSIZE/sizeof(long)];
static char *allocp1;
static char *ext_heapbase, *ext_heapspace, *ext_heapend;
/* GetMemory():
* This function is called by the guts of malloc when it needs to expand
* the size of the heap. Initially, GetMemory() will allocate memory
* from a static array (allocbuf[]) that is allocated memory space when the
* monitor is built. If the variable ext_heapbase is non-zero
* at the point when GetMemory() runs out of space in allocbuf[], it
* will start allocating memory from the block pointed to by ext_heapspase
* and ext_heapsize.
* WARNING: this feature can only be used if the malloc()/free() code
* can handle the fact that memory within its heap will be different
* blocks of non-contiguous space.
*/
char *
GetMemory(int n)
{
if(!allocp1) {
allocp1 = (char *)allocbuf;
}
/* First try to allocate from allocbuf[]... */
if(allocp1 + n <= (char *)allocbuf + ALLOCSIZE) {
allocp1 += n;
return (allocp1 - n);
}
/* Else try to allocated from the extended heap (if one)... */
else if(ext_heapbase) {
if(ext_heapspace + n <= ext_heapend) {
ext_heapspace += n;
return(ext_heapspace - n);
} else {
return(NULL);
}
}
/* Else, no space left to allocate from. */
else {
return (NULL);
}
}
/* ExtendHeap():
* Called by the heap command to provide GetMemory() with more space.
* This function can be called through the monitor API.
*/
int
extendHeap(char *start, int size)
{
/* If the size is -1, then assume this is a release request. */
if(size == -1) {
return(releaseExtendedHeap(0));
}
/* If extension is already loaded, then return -1 for failure. */
if(ext_heapbase) {
return(-1);
}
if(inUmonBssSpace(start,start+size-1)) {
return(-2);
}
ext_heapbase = ext_heapspace = start;
ext_heapend = start + size;
return(0);
}
/* UnextendHeap():
* Called by the heap command to "undo" the memory extension.
*/
void
unExtendHeap(void)
{
ext_heapbase = ext_heapspace = ext_heapend = 0;
}
char *
getExtHeapBase(void)
{
return(ext_heapbase);
}
/* GetMemoryLeft():
* Return the amount of memory that has yet to be allocated from
* the static and extended heap (if one).
*/
int
GetMemoryLeft(void)
{
int spaceleft;
if(!allocp1) {
allocp1 = (char *)allocbuf;
}
spaceleft = ((char *)allocbuf + ALLOCSIZE) - allocp1;
if(ext_heapbase) {
spaceleft += (ext_heapend - ext_heapspace);
}
return(spaceleft);
}
#else
int
extendHeap(char *start, int size)
{
return(-1);
}
#endif
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