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