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  * The functions in this file aren't called directly, but are required by
10  * GCC builtins such as __builtin_ctz, and therefore they can't be removed
11  * despite appearing unreferenced in kernel source.
12  *
13  * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
14  */
15 
16 #include <linux/export.h>
17 #include <linux/kernel.h>
18 
19 int __weak __ctzsi2(int val);
__ctzsi2(int val)20 int __weak __ctzsi2(int val)
21 {
22 	return __ffs(val);
23 }
24 EXPORT_SYMBOL(__ctzsi2);
25 
26 int __weak __clzsi2(int val);
__clzsi2(int val)27 int __weak __clzsi2(int val)
28 {
29 	return 32 - fls(val);
30 }
31 EXPORT_SYMBOL(__clzsi2);
32 
33 int __weak __clzdi2(long val);
34 int __weak __ctzdi2(long val);
35 #if BITS_PER_LONG == 32
36 
__clzdi2(long val)37 int __weak __clzdi2(long val)
38 {
39 	return 32 - fls((int)val);
40 }
41 EXPORT_SYMBOL(__clzdi2);
42 
__ctzdi2(long val)43 int __weak __ctzdi2(long val)
44 {
45 	return __ffs((u32)val);
46 }
47 EXPORT_SYMBOL(__ctzdi2);
48 
49 #elif BITS_PER_LONG == 64
50 
__clzdi2(long val)51 int __weak __clzdi2(long val)
52 {
53 	return 64 - fls64((u64)val);
54 }
55 EXPORT_SYMBOL(__clzdi2);
56 
__ctzdi2(long val)57 int __weak __ctzdi2(long val)
58 {
59 	return __ffs64((u64)val);
60 }
61 EXPORT_SYMBOL(__ctzdi2);
62 
63 #else
64 #error BITS_PER_LONG not 32 or 64
65 #endif
66