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/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chmem.h
* @brief Memory alignment macros and structures.
*
* @addtogroup mem
* @{
*/
#ifndef _CHALIGN_H_
#define _CHALIGN_H_
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
/*===========================================================================*/
/* Module data structures and types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module macros. */
/*===========================================================================*/
/**
* @name Memory alignment support macros
*/
/**
* @brief Alignment mask constant.
*
* @param[in] a alignment, must be a power of two
*/
#define MEM_ALIGN_MASK(a) ((size_t)(a) - 1U)
/**
* @brief Aligns to the previous aligned memory address.
*
* @param[in] p variable to be aligned
* @param[in] a alignment, must be a power of two
*/
#define MEM_ALIGN_PREV(p, a) ((size_t)(p) & ~MEM_ALIGN_MASK(a))
/**
* @brief Aligns to the new aligned memory address.
*
* @param[in] p variable to be aligned
* @param[in] a alignment, must be a power of two
*/
#define MEM_ALIGN_NEXT(p, a) MEM_ALIGN_PREV((size_t)(p) + \
MEM_ALIGN_MASK(a), (a))
/**
* @brief Returns whatever a pointer or memory size is aligned.
*
* @param[in] p variable to be aligned
* @param[in] a alignment, must be a power of two
*/
#define MEM_IS_ALIGNED(p, a) (((size_t)(p) & MEM_ALIGN_MASK(a)) == 0U)
/**
* @brief Returns whatever a constant is a valid alignment.
* @details Valid alignments are powers of two.
*
* @param[in] a alignment to be checked, must be a constant
*/
#define MEM_IS_VALID_ALIGNMENT(a) \
(((size_t)(a) != 0U) && (((size_t)(a) & ((size_t)(a) - 1U)) == 0U))
/** @} */
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
#ifdef __cplusplus
extern "C" {
#endif
#ifdef __cplusplus
}
#endif
/*===========================================================================*/
/* Module inline functions. */
/*===========================================================================*/
#endif /* _CHALIGN_H_ */
/** @} */
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