source: mainline/kernel/generic/include/align.h

Last change on this file was 096c0786, checked in by Jiří Zárevúcky <zarevucky.jiri@…>, 10 months ago

Ensure ALIGN_UP/DOWN() work with any size arguments

  • Property mode set to 100644
File size: 2.4 KB
Line 
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#ifdef __ASSEMBLER__
42#define ALIGN_DOWN(s, a) ((s) & ~((a) - 1))
43#define ALIGN_UP(s, a) (((s) + ((a) - 1)) & ~((a) - 1))
44#else
45
46/** Align to the nearest lower address.
47 *
48 * @param s Address or size to be aligned.
49 * @param a Size of alignment, must be a power of 2.
50 */
51#define ALIGN_DOWN(s, a) ((s) & ~((typeof(s))(a) - 1))
52
53/** Align to the nearest higher address.
54 *
55 * @param s Address or size to be aligned.
56 * @param a Size of alignment, must be a power of 2.
57 */
58#define ALIGN_UP(s, a) (((s) + ((a) - 1)) & ~((typeof(s))(a) - 1))
59
60#endif
61
62/** Check alignment.
63 *
64 * @param s Address or size to be checked for alignment.
65 * @param a Size of alignment, must be a power of 2.
66 */
67#define IS_ALIGNED(s, a) (ALIGN_UP((s), (a)) == (s))
68
69#endif
70
71/** @}
72 */
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