sysdeps/arm/armv6t2/ffs.S

   1 /* ffs -- find first set bit in an int, from least significant end.
   2    Copyright (C) 2013-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <sysdep.h>
  20
  21         .syntax unified
  22         .text
  23
  24 ENTRY (__ffs)
  25         cmp     r0, #0
  26         rbit    r0, r0
  27         itt     ne
  28         clzne   r0, r0
  29         addne   r0, r0, #1
  30         bx      lr
  31 END (__ffs)
  32
  33 weak_alias (__ffs, ffs)
  34 weak_alias (__ffs, ffsl)
  35 libc_hidden_def (__ffs)
  36 libc_hidden_builtin_def (ffs)