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/* Linuxthreads - a simple clone()-based implementation of Posix */
/* threads for Linux. */
/* Copyright (C) 1998 Xavier Leroy (Xavier.Leroy@inria.fr) */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Library General Public License */
/* as published by the Free Software Foundation; either version 2 */
/* of the License, or (at your option) any later version. */
/* */
/* This program 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 Library General Public License for more details. */
#if defined(TEST_FOR_COMPARE_AND_SWAP)
extern int __pthread_has_cas;
extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
int * spinlock);
static inline int compare_and_swap(long * ptr, long oldval, long newval,
int * spinlock)
{
if (__builtin_expect (__pthread_has_cas, 1))
return __compare_and_swap(ptr, oldval, newval);
else
return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
}
#elif defined(HAS_COMPARE_AND_SWAP)
static inline int compare_and_swap(long * ptr, long oldval, long newval,
int * spinlock)
{
return __compare_and_swap(ptr, oldval, newval);
}
#else
extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
int * spinlock);
static inline int compare_and_swap(long * ptr, long oldval, long newval,
int * spinlock)
{
return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
}
#endif
/* Internal locks */
extern void internal_function __pthread_lock(pthread_spinlock_t * lock,
pthread_descr self);
extern int __pthread_spin_unlock(pthread_spinlock_t *lock);
static inline void __pthread_init_lock(pthread_spinlock_t * lock)
{
lock->__status = 0;
lock->__spinlock = 0;
}
static inline int __pthread_trylock (pthread_spinlock_t * lock)
{
long oldstatus;
do {
oldstatus = lock->__status;
if (oldstatus != 0) return EBUSY;
} while(! compare_and_swap(&lock->__status, 0, 1, &lock->__spinlock));
return 0;
}
#define LOCK_INITIALIZER {0, 0}
/* Operations on pthread_atomic, which is defined in internals.h */
static inline long atomic_increment(struct pthread_atomic *pa)
{
long oldval;
do {
oldval = pa->p_count;
} while (!compare_and_swap(&pa->p_count, oldval, oldval + 1, &pa->p_spinlock));
return oldval;
}
static inline long atomic_decrement(struct pthread_atomic *pa)
{
long oldval;
do {
oldval = pa->p_count;
} while (!compare_and_swap(&pa->p_count, oldval, oldval - 1, &pa->p_spinlock));
return oldval;
}
#define ATOMIC_INITIALIZER { 0, 0 }
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