Increase program data space. As malloc and related functions depend on this, it is useful to have a working implementation. The following suffices for a standalone system; it exploits the symbol _end automatically defined by the GNU linker.
caddr_t sbrk(int incr) {
extern char _end; /* Defined by the linker */
static char *heap_end;
char *prev_heap_end;
if (heap_end == 0) {
heap_end = &_end;
}
prev_heap_end = heap_end;
if (heap_end + incr > stack_ptr) {
write (1, "Heap and stack collision\n", 25);
abort ();
}
heap_end += incr;
return (caddr_t) prev_heap_end;
}
tengyifei
commented
8 years ago
Increase program data space. As malloc and related functions depend on this, it is useful to have a working implementation. The following suffices for a standalone system; it exploits the symbol _end automatically defined by the GNU linker.