nes-proj/os/sys/critical.h
2017-12-09 17:09:57 +00:00

93 lines
3.6 KiB
C

/*
* Copyright (c) 2017, George Oikonomou - http://www.spd.gr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* 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
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*---------------------------------------------------------------------------*/
/**
* \addtogroup sys
* @{
*
* \defgroup critical Critical sections
* @{
*
* Platform-independent functions for critical section entry and exit
*/
/*---------------------------------------------------------------------------*/
#ifndef CRITICAL_H_
#define CRITICAL_H_
/*---------------------------------------------------------------------------*/
#include "contiki.h"
#include "sys/memory-barrier.h"
#include "sys/int-master.h"
#include <stdint.h>
/*---------------------------------------------------------------------------*/
/**
* \brief Enter a critical section
* \return The status of the master interrupt before entering the critical
*
* This function will return the status of the master interrupt as it was
* before entering the critical section.
*
* The semantics of the return value are entirely platform-specific. The
* calling code should not try to determine whether the master interrupt was
* previously enabled/disabled by interpreting the return value of this
* function. The return value should only be used as an argument to
* critical_exit().
*/
static inline int_master_status_t
critical_enter()
{
int_master_status_t status = int_master_read_and_disable();
memory_barrier();
return status;
}
/*---------------------------------------------------------------------------*/
/**
* \brief Exit a critical section and restore the master interrupt
* \param status The new status of the master interrupt
*
* The semantics of \e status are platform-dependent. Normally, the argument
* provided to this function will be a value previously retrieved through a
* call to critical_enter().
*/
static inline void
critical_exit(int_master_status_t status)
{
memory_barrier();
int_master_status_set(status);
}
/*---------------------------------------------------------------------------*/
#endif /* CRITICAL_H_ */
/*---------------------------------------------------------------------------*/
/**
* @}
* @}
*/