linuxthreads/sysdeps/powerpc/powerpc64/pspinlock.c

   1 /* POSIX spinlock implementation.  PowerPC version.
   2    Copyright (C) 2000, 2003 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 int
  25 __pthread_spin_lock (pthread_spinlock_t *lock)
  26 {
  27   while (! __compare_and_swap32 ((int *)lock, 0, 1))
  28     ;
  29   return 0;
  30 }
  31 weak_alias (__pthread_spin_lock, pthread_spin_lock)
  32
  33
  34 int
  35 __pthread_spin_trylock (pthread_spinlock_t *lock)
  36 {
  37   return __compare_and_swap32 ((int *)lock, 0, 1) ? 0 : EBUSY;
  38 }
  39 weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
  40
  41
  42 int
  43 __pthread_spin_unlock (pthread_spinlock_t *lock)
  44 {
  45   MEMORY_BARRIER ();
  46   *lock = 0;
  47   return 0;
  48 }
  49 weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
  50
  51
  52 int
  53 __pthread_spin_init (pthread_spinlock_t *lock, int pshared)
  54 {
  55   /* We can ignore the `pshared' parameter.  Since we are busy-waiting
  56      all processes which can access the memory location `lock' points
  57      to can use the spinlock.  */
  58   *lock = 0;
  59   return 0;
  60 }
  61 weak_alias (__pthread_spin_init, pthread_spin_init)
  62
  63
  64 int
  65 __pthread_spin_destroy (pthread_spinlock_t *lock)
  66 {
  67   /* Nothing to do.  */
  68   return 0;
  69 }
  70 weak_alias (__pthread_spin_destroy, pthread_spin_destroy)