View source for How does Optlib initialize the heap?

== '''How does Optlib initialize the heap? (RL78, RX, ARM targets)''' ==



Using the '''Optimized Library''', the heap space is set between 2 pointers when '''malloc()''' is first called:

  _heap_of_memory
  _top_of_heap()

_top_of_heap() returns a pointer to the stack pointer:

  char* _top_of_heap(void)
  {
  	return stack_ptr;
  }

_heap_of memory is set as the address of the label '''_end'''. The label is found by default in the project linker script (Debug/projectName_Debug_auto.'''gsi''') as the end of the '''.bss''' section.
The Optlib uses it to initialize the start of the heap:

  if(_heap_of_memory == NULL)
  {
  	_heap_of_memory = &end;
  	_last_heap_object = &end;
  }

If an user wants to define his own heap space with a desired length, he can do that by overwriting the address that the '''_heap_of_memory''' and '''_last_heap_object''' get and the address that '''_top_of_heap()''' returns.

'''NOTE:''' Make sure that the given addresses are not reserved and they are part of the RAM section!