xref: /linux/lib/clz_ctz.c (revision c4c11dd160a8cc98f402c4e12f94b1572e822ffd)
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 
16 int __weak __ctzsi2(int val)
17 {
18 	return __ffs(val);
19 }
20 EXPORT_SYMBOL(__ctzsi2);
21 
22 int __weak __clzsi2(int val)
23 {
24 	return 32 - fls(val);
25 }
26 EXPORT_SYMBOL(__clzsi2);
27 
28 #if BITS_PER_LONG == 32
29 
30 int __weak __clzdi2(long val)
31 {
32 	return 32 - fls((int)val);
33 }
34 EXPORT_SYMBOL(__clzdi2);
35 
36 int __weak __ctzdi2(long val)
37 {
38 	return __ffs((u32)val);
39 }
40 EXPORT_SYMBOL(__ctzdi2);
41 
42 #elif BITS_PER_LONG == 64
43 
44 int __weak __clzdi2(long val)
45 {
46 	return 64 - fls64((u64)val);
47 }
48 EXPORT_SYMBOL(__clzdi2);
49 
50 int __weak __ctzdi2(long val)
51 {
52 	return __ffs64((u64)val);
53 }
54 EXPORT_SYMBOL(__ctzdi2);
55 
56 #else
57 #error BITS_PER_LONG not 32 or 64
58 #endif
59