fb11e647
 vrobic
reseau statique a...
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/*
* Copyright (C) 2014-2015 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup cpu_cortexm_common
* @{
*
* @file
* @brief Implementation of the kernels atomic interface
*
* @author Stefan Pfeiffer <stefan.pfeiffer@fu-berlin.de>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Joakim Nohlgård <joakim.nohlgard@eistec.se>
*
* @}
*/
#include <stdint.h>
#include "atomic.h"
#include "irq.h"
#include "cpu.h"
#if ARCH_HAS_ATOMIC_COMPARE_AND_SWAP
int atomic_cas(atomic_int_t *var, int old, int now)
{
int tmp;
int status;
/* Load exclusive */
tmp = __LDREXW((volatile uint32_t *)(&ATOMIC_VALUE(*var)));
if (tmp != old) {
/* Clear memory exclusivity */
__CLREX();
return 0;
}
/* Try to write the new value */
status = __STREXW(now, (volatile uint32_t *)(&ATOMIC_VALUE(*var)));
return (status == 0);
}
#endif
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