xref: /OK3568_Linux_fs/kernel/lib/clz_ctz.c (revision 4882a59341e53eb6f0b4789bf948001014eff981) 
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  * lib/clz_ctz.c
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * Copyright (C) 2013 Chanho Min <chanho.min@lge.com>
6*4882a593Smuzhiyun  *
7*4882a593Smuzhiyun  * The functions in this file aren't called directly, but are required by
8*4882a593Smuzhiyun  * GCC builtins such as __builtin_ctz, and therefore they can't be removed
9*4882a593Smuzhiyun  * despite appearing unreferenced in kernel source.
10*4882a593Smuzhiyun  *
11*4882a593Smuzhiyun  * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
12*4882a593Smuzhiyun  */
13*4882a593Smuzhiyun 
14*4882a593Smuzhiyun #include <linux/export.h>
15*4882a593Smuzhiyun #include <linux/kernel.h>
16*4882a593Smuzhiyun 
17*4882a593Smuzhiyun int __weak __ctzsi2(int val);
__ctzsi2(int val)18*4882a593Smuzhiyun int __weak __ctzsi2(int val)
19*4882a593Smuzhiyun {
20*4882a593Smuzhiyun 	return __ffs(val);
21*4882a593Smuzhiyun }
22*4882a593Smuzhiyun EXPORT_SYMBOL(__ctzsi2);
23*4882a593Smuzhiyun 
24*4882a593Smuzhiyun int __weak __clzsi2(int val);
__clzsi2(int val)25*4882a593Smuzhiyun int __weak __clzsi2(int val)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun 	return 32 - fls(val);
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun EXPORT_SYMBOL(__clzsi2);
30*4882a593Smuzhiyun 
31*4882a593Smuzhiyun int __weak __clzdi2(long val);
32*4882a593Smuzhiyun int __weak __ctzdi2(long val);
33*4882a593Smuzhiyun #if BITS_PER_LONG == 32
34*4882a593Smuzhiyun 
__clzdi2(long val)35*4882a593Smuzhiyun int __weak __clzdi2(long val)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun 	return 32 - fls((int)val);
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun EXPORT_SYMBOL(__clzdi2);
40*4882a593Smuzhiyun 
__ctzdi2(long val)41*4882a593Smuzhiyun int __weak __ctzdi2(long val)
42*4882a593Smuzhiyun {
43*4882a593Smuzhiyun 	return __ffs((u32)val);
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun EXPORT_SYMBOL(__ctzdi2);
46*4882a593Smuzhiyun 
47*4882a593Smuzhiyun #elif BITS_PER_LONG == 64
48*4882a593Smuzhiyun 
__clzdi2(long val)49*4882a593Smuzhiyun int __weak __clzdi2(long val)
50*4882a593Smuzhiyun {
51*4882a593Smuzhiyun 	return 64 - fls64((u64)val);
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun EXPORT_SYMBOL(__clzdi2);
54*4882a593Smuzhiyun 
__ctzdi2(long val)55*4882a593Smuzhiyun int __weak __ctzdi2(long val)
56*4882a593Smuzhiyun {
57*4882a593Smuzhiyun 	return __ffs64((u64)val);
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun EXPORT_SYMBOL(__ctzdi2);
60*4882a593Smuzhiyun 
61*4882a593Smuzhiyun #else
62*4882a593Smuzhiyun #error BITS_PER_LONG not 32 or 64
63*4882a593Smuzhiyun #endif
64