linuxthreads/sysdeps/cris/pspinlock.c

   1 /* POSIX spinlock implementation.  CRIS version.
   2    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <pthread.h>
  22 #include "internals.h"
  23
  24 /* FIXME: These are just dummies.  I don't know why or if they're needed;
  25    configury should default to these definitions.  We just follow the
  26    crowd here.  */
  27
  28 int
  29 __pthread_spin_lock (pthread_spinlock_t *lock)
  30 {
  31   while (testandset (lock) != 0)
  32     ;
  33
  34   return 0;
  35 }
  36 weak_alias (__pthread_spin_lock, pthread_spin_lock)
  37
  38
  39 int
  40 __pthread_spin_trylock (pthread_spinlock_t *lock)
  41 {
  42   return testandset (lock) != 0 ? EBUSY : 0;
  43 }
  44 weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
  45
  46
  47 int
  48 __pthread_spin_unlock (pthread_spinlock_t *lock)
  49 {
  50   return *lock = 0;
  51 }
  52 weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
  53
  54
  55 int
  56 __pthread_spin_init (pthread_spinlock_t *lock, int pshared)
  57 {
  58   /* We can ignore the `pshared' parameter.  Since we are busy-waiting
  59      all processes which can access the memory location `lock' points
  60      to can use the spinlock.  */
  61   return *lock = 0;
  62 }
  63 weak_alias (__pthread_spin_init, pthread_spin_init)
  64
  65
  66 int
  67 __pthread_spin_destroy (pthread_spinlock_t *lock)
  68 {
  69   /* Nothing to do.  */
  70   return 0;
  71 }
  72 weak_alias (__pthread_spin_destroy, pthread_spin_destroy)