Root/lib/clz_ctz.c

1/*
2 * lib/clz_ctz.c
3 *
4 * Copyright (C) 2013 Chanho Min <chanho.min@lge.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
11 */
12
13#include <linux/export.h>
14#include <linux/kernel.h>
15
16int __weak __ctzsi2(int val)
17{
18    return __ffs(val);
19}
20EXPORT_SYMBOL(__ctzsi2);
21
22int __weak __clzsi2(int val)
23{
24    return 32 - fls(val);
25}
26EXPORT_SYMBOL(__clzsi2);
27
28#if BITS_PER_LONG == 32
29
30int __weak __clzdi2(long val)
31{
32    return 32 - fls((int)val);
33}
34EXPORT_SYMBOL(__clzdi2);
35
36int __weak __ctzdi2(long val)
37{
38    return __ffs((u32)val);
39}
40EXPORT_SYMBOL(__ctzdi2);
41
42#elif BITS_PER_LONG == 64
43
44int __weak __clzdi2(long val)
45{
46    return 64 - fls64((u64)val);
47}
48EXPORT_SYMBOL(__clzdi2);
49
50int __weak __ctzdi2(long val)
51{
52    return __ffs64((u64)val);
53}
54EXPORT_SYMBOL(__ctzdi2);
55
56#else
57#error BITS_PER_LONG not 32 or 64
58#endif
59

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