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/* POSIX spinlock implementation. ia64 version.
Copyright (C) 2000, 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jes Sorensen <jes@linuxcare.com>
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <pthread.h>
#include "internals.h"
#include <ia64intrin.h>
/* This implementation is inspired by the implementation used in the
Linux kernel. */
int
__pthread_spin_lock (pthread_spinlock_t *lock)
{
int *p = (int *) lock;
while (__builtin_expect (__sync_val_compare_and_swap_si (p, 0, 1), 0))
{
/* Spin without using the atomic instruction. */
do
__asm __volatile ("" : : : "memory");
while (*p);
}
return 0;
}
weak_alias (__pthread_spin_lock, pthread_spin_lock)
int
__pthread_spin_trylock (pthread_spinlock_t *lock)
{
return __sync_val_compare_and_swap_si ((int *) lock, 0, 1) == 0 ? 0 : EBUSY;
}
weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
int
__pthread_spin_unlock (pthread_spinlock_t *lock)
{
return *lock = 0;
}
weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
int
__pthread_spin_init (pthread_spinlock_t *lock, int pshared)
{
/* We can ignore the `pshared' parameter. Since we are busy-waiting
all processes which can access the memory location `lock' points
to can use the spinlock. */
return *lock = 0;
}
weak_alias (__pthread_spin_init, pthread_spin_init)
int
__pthread_spin_destroy (pthread_spinlock_t *lock)
{
/* Nothing to do. */
return 0;
}
weak_alias (__pthread_spin_destroy, pthread_spin_destroy)
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