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Not all gcc configurations have an implementation of all the atomic operations, and some gcc configurations have some atomic builtins implemented but not all. Thus check for the most essential function, whose presence should indicate that all others are present as well, since it can be used to implement all the other ones. Signed-off-by: Martin Storsjö <martin@martin.st>
124 lines
2.7 KiB
C
124 lines
2.7 KiB
C
/*
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* Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "atomic.h"
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#if !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER
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#if HAVE_PTHREADS
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#include <pthread.h>
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static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER;
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int avpriv_atomic_int_get(volatile int *ptr)
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{
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int res;
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pthread_mutex_lock(&atomic_lock);
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res = *ptr;
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pthread_mutex_unlock(&atomic_lock);
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return res;
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}
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void avpriv_atomic_int_set(volatile int *ptr, int val)
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{
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pthread_mutex_lock(&atomic_lock);
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*ptr = val;
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pthread_mutex_unlock(&atomic_lock);
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}
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int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
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{
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int res;
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pthread_mutex_lock(&atomic_lock);
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*ptr += inc;
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res = *ptr;
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pthread_mutex_unlock(&atomic_lock);
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return res;
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}
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void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
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{
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void *ret;
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pthread_mutex_lock(&atomic_lock);
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ret = *ptr;
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if (*ptr == oldval)
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*ptr = newval;
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pthread_mutex_unlock(&atomic_lock);
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return ret;
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}
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#elif !HAVE_THREADS
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int avpriv_atomic_int_get(volatile int *ptr)
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{
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return *ptr;
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}
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void avpriv_atomic_int_set(volatile int *ptr, int val)
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{
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*ptr = val;
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}
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int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
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{
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*ptr += inc;
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return *ptr;
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}
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void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
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{
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if (*ptr == oldval) {
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*ptr = newval;
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return oldval;
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}
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return *ptr;
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}
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#else
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#error "Threading is enabled, but there is no implementation of atomic operations available"
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#endif /* HAVE_PTHREADS */
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#endif /* !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER */
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#ifdef TEST
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#include <assert.h>
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int main(void)
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{
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volatile int val = 1;
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int res;
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res = avpriv_atomic_int_add_and_fetch(&val, 1);
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assert(res == 2);
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avpriv_atomic_int_set(&val, 3);
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res = avpriv_atomic_int_get(&val);
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assert(res == 3);
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return 0;
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}
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#endif
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