cpu/avr/avr.c

   1 #include <avr/io.h>
   2
   3 #include "contiki-conf.h"
   4
   5 void
   6 cpu_init(void)
   7 {
   8   asm volatile ("clr r1");      /* No longer needed. */
   9 }
  10
  11 extern int __bss_end;
  12
  13 #define STACK_EXTRA 32
  14 static char *cur_break = (char *)(&__bss_end + 1);
  15
  16 /*
  17  * Allocate memory from the heap. Check that we don't collide with the
  18  * stack right now (some other routine might later). A watchdog might
  19  * be used to check if cur_break and the stack pointer meet during
  20  * runtime.
  21  */
  22 void *
  23 sbrk(int incr)
  24 {
  25   char *stack_pointer;
  26
  27   stack_pointer = (char *)SP;
  28   stack_pointer -= STACK_EXTRA;
  29   if(incr > (stack_pointer - cur_break))
  30     return (void *)-1;          /* ENOMEM */
  31
  32   void *old_break = cur_break;
  33   cur_break += incr;
  34   /*
  35    * If the stack was never here then [old_break .. cur_break] should
  36    * be filled with zeros.
  37   */
  38   return old_break;
  39 }