clz_ctz.c 899 B

12345678910111213141516171819202122232425262728293031323334353637383940414243
  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * lib/clz_ctz.c
  4. *
  5. * Copyright (C) 2013 Chanho Min <[email protected]>
  6. *
  7. * The functions in this file aren't called directly, but are required by
  8. * GCC builtins such as __builtin_ctz, and therefore they can't be removed
  9. * despite appearing unreferenced in kernel source.
  10. *
  11. * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
  12. */
  13. #include <linux/export.h>
  14. #include <linux/kernel.h>
  15. int __weak __ctzsi2(int val);
  16. int __weak __ctzsi2(int val)
  17. {
  18. return __ffs(val);
  19. }
  20. EXPORT_SYMBOL(__ctzsi2);
  21. int __weak __clzsi2(int val);
  22. int __weak __clzsi2(int val)
  23. {
  24. return 32 - fls(val);
  25. }
  26. EXPORT_SYMBOL(__clzsi2);
  27. int __weak __clzdi2(u64 val);
  28. int __weak __clzdi2(u64 val)
  29. {
  30. return 64 - fls64(val);
  31. }
  32. EXPORT_SYMBOL(__clzdi2);
  33. int __weak __ctzdi2(u64 val);
  34. int __weak __ctzdi2(u64 val)
  35. {
  36. return __ffs64(val);
  37. }
  38. EXPORT_SYMBOL(__ctzdi2);