uspace/lib/c/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 libc
  30  * @{
  31  */
  32 /** @file
  33  */
  34
  35 #ifndef _LIBC_ALIGN_H_
  36 #define _LIBC_ALIGN_H_
  37
  38 /** Align to the nearest lower address which is a power of two.
  39  *
  40  * @param s             Address or size to be aligned.
  41  * @param a             Size of alignment, must be power of 2.
  42  */
  43 #define ALIGN_DOWN(s, a)        ((s) & ~((typeof(s))(a) - 1))
  44
  45 /** Align to the nearest higher address which is a power of two.
  46  *
  47  * @param s             Address or size to be aligned.
  48  * @param a             Size of alignment, must be power of 2.
  49  */
  50 #define ALIGN_UP(s, a)          ((((s) + ((a) - 1)) & ~((typeof(s))(a) - 1)))
  51
  52 /** Round up to the nearest higher boundary.
  53  *
  54  * @param n             Number to be aligned.
  55  * @param b             Boundary, arbitrary unsigned number.
  56  */
  57 #define ROUND_UP(n, b)          (((n) / (b) + ((n) % (b) != 0)) * (b))
  58
  59 #endif
  60
  61 /** @}
  62  */