print from flash memory broken on DUE?

Hardware Arduino Due
7

zachtos:
... and the RAM function I run will show FREE RAM go up alot when converting to flash memory storage.

int freeRam(void)

{
  extern int  __bss_end;
  extern int  *__brkval;
  int free_memory;
  if((int)__brkval == 0) {
    free_memory = ((int)&free_memory) - ((int)&__bss_end);
  }
  else {
    free_memory = ((int)&free_memory) - ((int)__brkval);
  }
  return free_memory;
}
}

Had tried that a while ago. I could not figure out how to get __bss_end and __brkval defined...