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
  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