LXR linux/lib/clz

   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