kernel/generic/include/align.h

   1 /*
   2  * Copyright (c) 2005 Jakub Jermar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup kernel_generic
  30  * @ingroup others
  31  * @{
  32  */
  33 /**
  34  * @file
  35  * @brief Macros for making values and addresses aligned.
  36  */
  37
  38 #ifndef KERN_ALIGN_H_
  39 #define KERN_ALIGN_H_
  40
  41 /** Align to the nearest lower address.
  42  *
  43  * @param s Address or size to be aligned.
  44  * @param a Size of alignment, must be a power of 2.
  45  */
  46 #define ALIGN_DOWN(s, a)  ((s) & ~((a) - 1))
  47
  48 /** Align to the nearest higher address.
  49  *
  50  * @param s Address or size to be aligned.
  51  * @param a Size of alignment, must be a power of 2.
  52  */
  53 #define ALIGN_UP(s, a)  (((s) + ((a) - 1)) & ~((a) - 1))
  54
  55 /** Check alignment.
  56  *
  57  * @param s Address or size to be checked for alignment.
  58  * @param a Size of alignment, must be a power of 2.
  59  */
  60 #define IS_ALIGNED(s, a)        (ALIGN_UP((s), (a)) == (s))
  61
  62 #endif
  63
  64 /** @}
  65  */