ffs.c 1.3 KB

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  1. /* ffs -- find first set bit in a word, counted from least significant end.
  2. For mc68020, mc68030, mc68040.
  3. This file is part of the GNU C Library.
  4. Copyright (C) 1991-2019 Free Software Foundation, Inc.
  5. Contributed by Torbjorn Granlund (tege@sics.se).
  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. 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. You should have received a copy of the GNU Lesser General Public
  15. License along with the GNU C Library. If not, see
  16. <http://www.gnu.org/licenses/>. */
  17. #define ffsl __something_else
  18. #include <string.h>
  19. #undef ffs
  20. #if defined (__GNUC__) && defined (__mc68020__)
  21. int
  22. __ffs (int x)
  23. {
  24. int cnt;
  25. asm ("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));
  26. return 32 - cnt;
  27. }
  28. weak_alias (__ffs, ffs)
  29. libc_hidden_def (__ffs)
  30. libc_hidden_builtin_def (ffs)
  31. #undef ffsl
  32. weak_alias (__ffs, ffsl)
  33. #else
  34. #include <string/ffs.c>
  35. #endif