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/arch/mn10300/lib/bitops.c

http://github.com/mirrors/linux
C | 50 lines | 26 code | 8 blank | 16 comment | 6 complexity | e77fd2f3d3fa6aa7056356d1698b5572 MD5 | raw file
 1/* MN10300 Non-trivial bit operations
 2 *
 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 4 * Written by David Howells (dhowells@redhat.com)
 5 *
 6 * This program is free software; you can redistribute it and/or
 7 * modify it under the terms of the GNU General Public Licence
 8 * as published by the Free Software Foundation; either version
 9 * 2 of the Licence, or (at your option) any later version.
10 */
11#include <linux/module.h>
12#include <asm/bitops.h>
13
14/*
15 * try flipping a bit using BSET and BCLR
16 */
17void change_bit(unsigned long nr, volatile void *addr)
18{
19	if (test_bit(nr, addr))
20		goto try_clear_bit;
21
22try_set_bit:
23	if (!test_and_set_bit(nr, addr))
24		return;
25
26try_clear_bit:
27	if (test_and_clear_bit(nr, addr))
28		return;
29
30	goto try_set_bit;
31}
32
33/*
34 * try flipping a bit using BSET and BCLR and returning the old value
35 */
36int test_and_change_bit(unsigned long nr, volatile void *addr)
37{
38	if (test_bit(nr, addr))
39		goto try_clear_bit;
40
41try_set_bit:
42	if (!test_and_set_bit(nr, addr))
43		return 0;
44
45try_clear_bit:
46	if (test_and_clear_bit(nr, addr))
47		return 1;
48
49	goto try_set_bit;
50}