string/ffsll.c

   1 /* Copyright (C) 1991-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Torbjorn Granlund (tege@sics.se).
   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 <limits.h>
  20 #define ffsl __something_else
  21 #include <string.h>
  22
  23 #undef  ffsll
  24
  25 /* Find the first bit set in I.  */
  26 int
  27 ffsll (long long int i)
  28 {
  29   unsigned long long int x = i & -i;
  30
  31   if (x <= 0xffffffff)
  32     return ffs (i);
  33   else
  34     return 32 + ffs (i >> 32);
  35 }
  36
  37 #if ULONG_MAX != UINT_MAX
  38 #undef ffsl
  39 weak_alias (ffsll, ffsl)
  40 #endif