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 */
change_bit(unsigned long nr,volatile void * addr)17 void change_bit(unsigned long nr, volatile void *addr)
18 {
19 if (test_bit(nr, addr))
20 goto try_clear_bit;
21
22 try_set_bit:
23 if (!test_and_set_bit(nr, addr))
24 return;
25
26 try_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 */
test_and_change_bit(unsigned long nr,volatile void * addr)36 int test_and_change_bit(unsigned long nr, volatile void *addr)
37 {
38 if (test_bit(nr, addr))
39 goto try_clear_bit;
40
41 try_set_bit:
42 if (!test_and_set_bit(nr, addr))
43 return 0;
44
45 try_clear_bit:
46 if (test_and_clear_bit(nr, addr))
47 return 1;
48
49 goto try_set_bit;
50 }
51