lib/clz_ctz.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * lib/clz_ctz.c
   4  *
   5  * Copyright (C) 2013 Chanho Min <chanho.min@lge.com>
   6  *
   7  * The functions in this file aren't called directly, but are required by
   8  * GCC builtins such as __builtin_ctz, and therefore they can't be removed
   9  * despite appearing unreferenced in kernel source.
  10  *
  11  * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
  12  */
  13
  14 #include <linux/export.h>
  15 #include <linux/kernel.h>
  16
  17 int __weak __ctzsi2(int val);
  18 int __weak __ctzsi2(int val)
  19 {
  20         return __ffs(val);
  21 }
  22 EXPORT_SYMBOL(__ctzsi2);
  23
  24 int __weak __clzsi2(int val);
  25 int __weak __clzsi2(int val)
  26 {
  27         return 32 - fls(val);
  28 }
  29 EXPORT_SYMBOL(__clzsi2);
  30
  31 int __weak __clzdi2(u64 val);
  32 int __weak __clzdi2(u64 val)
  33 {
  34         return 64 - fls64(val);
  35 }
  36 EXPORT_SYMBOL(__clzdi2);
  37
  38 int __weak __ctzdi2(u64 val);
  39 int __weak __ctzdi2(u64 val)
  40 {
  41         return __ffs64(val);
  42 }
  43 EXPORT_SYMBOL(__ctzdi2);