glibc/sysdeps/powerpc/ffs.c

/* Find first set bit in a word, counted from least significant end.
   For PowerPC.
   Copyright (C) 1991-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#define ffsl __something_else
#include <limits.h>
#include <string.h>

#undef	ffs

#ifdef 	__GNUC__

int
__ffs (int x)
{
  int cnt;

  asm ("cntlzw %0,%1" : "=r" (cnt) : "r" (x & -x));
  return 32 - cnt;
}
weak_alias (__ffs, ffs)
libc_hidden_def (__ffs)
libc_hidden_builtin_def (ffs)
#if ULONG_MAX == UINT_MAX
#undef ffsl
weak_alias (__ffs, ffsl)
#endif

#else
#include <string/ffs.c>
#endif