toolchain/gcc/newlib/libc/sys/arc/sbrk.c

   1 /* sbrk support */
   2
   3 /* The current plan is to have one sbrk handler for all cpus.
   4    Hence use `asm' for each global variable here to avoid the cpu prefix.
   5    We can't intrude on the user's namespace (another reason to use asm).  */
   6
   7 #include <sys/types.h>
   8 #include <sys/syscall.h>
   9 #include <errno.h>
  10 #include <stddef.h>
  11
  12 /* These variables are publicly accessible for debugging purposes.
  13    The user is also free to set sbrk_size to something different.
  14    See mem-layout.c.  */
  15
  16 extern int sbrk_size asm ("sbrk_size");
  17
  18 caddr_t sbrk_start asm ("sbrk_start");
  19 caddr_t sbrk_loc asm ("sbrk_loc");
  20
  21 /*caddr_t _sbrk_r (struct _reent *, size_t) asm ("__sbrk_r");*/
  22
  23 /* FIXME: We need a semaphore here.  */
  24
  25 caddr_t
  26 _sbrk_r (struct _reent *r, size_t nbytes)
  27 {
  28   caddr_t result;
  29
  30   if (
  31       /* Ensure we don't underflow.  */
  32       sbrk_loc + nbytes < sbrk_start
  33       /* Ensure we don't overflow.  */
  34       || sbrk_loc + nbytes > sbrk_start + sbrk_size)
  35     {
  36       errno = ENOMEM;
  37       return ((caddr_t) -1);
  38     }
  39
  40   result = sbrk_loc;
  41   sbrk_loc += nbytes;
  42   return result;
  43 }