extern C void SECTION(".entry") _entry()
{
int ret, argc;
char *arguments;
char **argv;
/* Setup the heap, C++ constructors and default mounts. */
setupHeap();
runConstructors();
setupMappings();
/* Allocate buffer for arguments. */
argc = 0;
argv = (char **) new char[ARGV_COUNT];
arguments = (char *) ARGV_ADDR;
/* Fill in arguments list. */
while (argc < ARGV_COUNT && *arguments)
{
argv[argc] = arguments;
arguments += ARGV_SIZE;
argc++;
}
/* Pass control to the program. */
ret = main(argc, argv);
/* Terminate execution. */
runDestructors();
exit(ret);
}
void* my_malloc(size_t size)
{
// calculate the needed size
int total_size = size + sizeof(metadata_t);
// if the requested size is beyond our largest block size
if (total_size > SBRK_SIZE) {
ERRNO = SINGLE_REQUEST_TOO_LARGE;
return NULL;
}
// set up the heap if it is uninitialized
if (!heap) {
setupHeap();
if (ERRNO == OUT_OF_MEMORY) {
return NULL;
}
}
// get index of the free list to allocate memory to the user
int idx = getIdx(total_size);
metadata_t *allocBlock = NULL;
// if we have a memory block to allocate
if (freelist[idx] != NULL) {
// just simply return the first block
allocBlock = freelist[idx];
// if there is the next block
if (allocBlock->next != NULL) {
allocBlock->next->prev = NULL;
freelist[idx] = allocBlock->next;
} else {
freelist[idx] = NULL;
}
// remove this block/
allocBlock->in_use = 1;
allocBlock->prev = NULL;
allocBlock->next = NULL;
// return the block
return ((char*)allocBlock + sizeof(metadata_t));
}
// if we do not have a memory block to allocate
// we split the second smallest blocks into blocks of needed size
int splitIdx = idx + 1;
while (freelist[splitIdx] == NULL) {
splitIdx++;
}
// if there are no blocks to split
if (splitIdx == 8) {
// set up a new heap
setupHeap();
if (ERRNO == OUT_OF_MEMORY) {
return NULL;
}
} else { // if a block can be split
splitBlock(splitIdx, idx, freelist[splitIdx]); // a recursive function
}
// call my_malloc() again to allocate memory
allocBlock = my_malloc(size);
// set the error code
ERRNO = NO_ERROR;
return allocBlock;
}