__sync built-ins are considered legacy and will be deprecated. These new memory model aware built-ins have been available since GCC 4.7.0 Use them by default when available except for __atomic_compare_exchange_n(), which is slower, and is instead implemented as a fallback for when and if gcc removes the legacy __sync built-ins. Reviewed-by: Michael Niedermayer <michaelni@gmx.at> Signed-off-by: James Almer <jamrial@gmail.com>
		
			
				
	
	
		
			79 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			79 lines
		
	
	
		
			2.3 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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#ifndef AVUTIL_ATOMIC_GCC_H
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#define AVUTIL_ATOMIC_GCC_H
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#include <stdint.h>
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#include "atomic.h"
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#define avpriv_atomic_int_get atomic_int_get_gcc
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static inline int atomic_int_get_gcc(volatile int *ptr)
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{
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#if HAVE_ATOMIC_COMPARE_EXCHANGE
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    return __atomic_load_n(ptr, __ATOMIC_SEQ_CST);
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#else
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    __sync_synchronize();
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    return *ptr;
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#endif
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}
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#define avpriv_atomic_int_set atomic_int_set_gcc
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static inline void atomic_int_set_gcc(volatile int *ptr, int val)
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{
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#if HAVE_ATOMIC_COMPARE_EXCHANGE
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    __atomic_store_n(ptr, val, __ATOMIC_SEQ_CST);
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#else
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    *ptr = val;
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    __sync_synchronize();
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#endif
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}
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#define avpriv_atomic_int_add_and_fetch atomic_int_add_and_fetch_gcc
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static inline int atomic_int_add_and_fetch_gcc(volatile int *ptr, int inc)
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{
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#if HAVE_ATOMIC_COMPARE_EXCHANGE
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    return __atomic_add_fetch(ptr, inc, __ATOMIC_SEQ_CST);
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#else
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    return __sync_add_and_fetch(ptr, inc);
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#endif
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}
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#define avpriv_atomic_ptr_cas atomic_ptr_cas_gcc
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static inline void *atomic_ptr_cas_gcc(void * volatile *ptr,
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                                       void *oldval, void *newval)
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{
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#if HAVE_SYNC_VAL_COMPARE_AND_SWAP
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#ifdef __ARMCC_VERSION
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    // armcc will throw an error if ptr is not an integer type
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    volatile uintptr_t *tmp = (volatile uintptr_t*)ptr;
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    return (void*)__sync_val_compare_and_swap(tmp, oldval, newval);
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#else
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    return __sync_val_compare_and_swap(ptr, oldval, newval);
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#endif
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#else
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    __atomic_compare_exchange_n(ptr, &oldval, newval, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
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    return oldval;
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#endif
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}
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#endif /* AVUTIL_ATOMIC_GCC_H */
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