ffsll.c 1.3 KB

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  1. /* Copyright (C) 1991-2026 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <https://www.gnu.org/licenses/>. */
  14. #include <limits.h>
  15. #define ffsl __something_else
  16. #include <string.h>
  17. #undef ffsll
  18. #include <math-use-builtins.h>
  19. #include <libc-diag.h>
  20. /* Find the first bit set in I. */
  21. int
  22. __ffsll (long long int i)
  23. {
  24. #if USE_FFSLL_BUILTIN
  25. return __builtin_ffsll (i);
  26. #else
  27. unsigned long long int x = i & -i;
  28. if (x <= 0xffffffff)
  29. return ffs (i);
  30. else
  31. return 32 + ffs (i >> 32);
  32. #endif
  33. }
  34. static_weak_alias (__ffsll, ffsll)
  35. #if ULONG_MAX != UINT_MAX
  36. #undef ffsl
  37. static_weak_alias (__ffsll, ffsl)
  38. #endif