linuxthreads/sysdeps/hppa/pspinlock.c

   1 /* POSIX spinlock implementation.  hppa version.
   2    Copyright (C) 2000 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   unsigned int val;
  28
  29   do
  30     asm volatile ("ldcw %1,%0"
  31                   : "=r" (val), "=m" (*lock)
  32                   : "m" (*lock));
  33   while (!val);
  34
  35   return 0;
  36 }
  37 weak_alias (__pthread_spin_lock, pthread_spin_lock)
  38
  39
  40 int
  41 __pthread_spin_trylock (pthread_spinlock_t *lock)
  42 {
  43   unsigned int val;
  44
  45   asm volatile ("ldcw %1,%0"
  46                 : "=r" (val), "=m" (*lock)
  47                 : "m" (*lock));
  48
  49   return val ? 0 : EBUSY;
  50 }
  51 weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
  52
  53
  54 int
  55 __pthread_spin_unlock (pthread_spinlock_t *lock)
  56 {
  57   *lock = 1;
  58   return 0;
  59 }
  60 weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
  61
  62
  63 int
  64 __pthread_spin_init (pthread_spinlock_t *lock, int pshared)
  65 {
  66   /* We can ignore the `pshared' parameter.  Since we are busy-waiting
  67      all processes which can access the memory location `lock' points
  68      to can use the spinlock.  */
  69   *lock = 1;
  70   return 0;
  71 }
  72 weak_alias (__pthread_spin_init, pthread_spin_init)
  73
  74
  75 int
  76 __pthread_spin_destroy (pthread_spinlock_t *lock)
  77 {
  78   /* Nothing to do.  */
  79   return 0;
  80 }
  81 weak_alias (__pthread_spin_destroy, pthread_spin_destroy)