sysdeps/powerpc/ffs.c

   1 /* Find first set bit in a word, counted from least significant end.
   2    For PowerPC.
   3    Copyright (C) 1991-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #define ffsl __something_else
  21 #include <limits.h>
  22 #include <string.h>
  23
  24 #undef  ffs
  25
  26 #ifdef  __GNUC__
  27
  28 int
  29 __ffs (int x)
  30 {
  31   int cnt;
  32
  33   asm ("cntlzw %0,%1" : "=r" (cnt) : "r" (x & -x));
  34   return 32 - cnt;
  35 }
  36 weak_alias (__ffs, ffs)
  37 libc_hidden_def (__ffs)
  38 libc_hidden_builtin_def (ffs)
  39 #if ULONG_MAX == UINT_MAX
  40 #undef ffsl
  41 weak_alias (__ffs, ffsl)
  42 #endif
  43
  44 #else
  45 #include <string/ffs.c>
  46 #endif