atomic.h

/*
 * Copyright (c) 2019, Toshiba Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
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 *
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 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
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 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 */
/*---------------------------------------------------------------------------*/
/**
 * \addtogroup sys
 * @{
 *
 * \defgroup atomic Atomic operations
 * @{
 *
 * This library provides an API and generic implementation of atomic
 * operations.
 *
 * The structure of this library is more or less the same as
 * sys/mutex. By default, atomic operations are implemented by
 * disabling interrupts temporarily. Platforms can provide better
 * implementation using platform-specific features.
 *
 */
#ifndef ATOMIC_H_
#define ATOMIC_H_

#include <contiki.h>
#include <stdint.h>
#include <stdbool.h>

#ifdef ATOMIC_CONF_ARCH_HEADER_PATH
#include ATOMIC_CONF_ARCH_HEADER_PATH
#endif /* ATOMIC_CONF_ARCH_HEADER_PATH */

/**
 * \brief Atomic compare-and-swap (CAS) on a byte.
 * 
 * This macro expands to atomic_generic_cas_uint8() or CPU-provided
 * implementation. Platform-independent code should use this macro
 * instead of atomic_generic_cas_uint8(). 
 */  
#ifndef atomic_cas_uint8
#define atomic_cas_uint8(t,o,n) atomic_generic_cas_uint8((t),(o),(n))
#endif /* atomic_cas_uint8 */

/**
 * \brief Atomic compare-and-swap (CAS) on a byte (generic impl.)
 * \param target Pointer to the target byte to manipulate.
 * \param old_val Value that is expected to be stored in the target.
 * \param new_val Value that it stores to the target.
 *
 * If value of target is equal to old_val, store new_val to
 * target. If the store operation succeeds, it returns true.
 * Otherwise, it just returns false without storing.
 */
bool atomic_generic_cas_uint8(uint8_t *target, uint8_t old_val, uint8_t new_val);

#endif /* ATOMIC_H_ */
/**
 * @}
 * @}
 */