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/* sbrk support */

/* The current plan is to have one sbrk handler for all cpus.

   Hence use `asm' for each global variable here to avoid the cpu prefix.

   We can't intrude on the user's namespace (another reason to use asm).  */

#include <sys/types.h>

#include <sys/syscall.h>

#include <errno.h>

#include <stddef.h>

/* These variables are publicly accessible for debugging purposes.

   The user is also free to set sbrk_size to something different.

   See mem-layout.c.  */

extern int sbrk_size asm ("sbrk_size");

caddr_t sbrk_start asm ("sbrk_start");

caddr_t sbrk_loc asm ("sbrk_loc");

/*caddr_t _sbrk_r (struct _reent *, size_t) asm ("__sbrk_r");*/

/* FIXME: We need a semaphore here.  */

caddr_t

_sbrk_r (struct _reent *r, size_t nbytes)

{

  caddr_t result;

  if (

      /* Ensure we don't underflow.  */

      sbrk_loc + nbytes < sbrk_start

      /* Ensure we don't overflow.  */

      || sbrk_loc + nbytes > sbrk_start + sbrk_size)

    {

      errno = ENOMEM;

      return ((caddr_t) -1);

    }

  result = sbrk_loc;

  sbrk_loc += nbytes;

  return result;

}