const_hweight.h 1.7 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
  3. #define _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
  4. /*
  5. * Compile time versions of __arch_hweightN()
  6. */
  7. #define __const_hweight8(w) \
  8. ((unsigned int) \
  9. ((!!((w) & (1ULL << 0))) + \
  10. (!!((w) & (1ULL << 1))) + \
  11. (!!((w) & (1ULL << 2))) + \
  12. (!!((w) & (1ULL << 3))) + \
  13. (!!((w) & (1ULL << 4))) + \
  14. (!!((w) & (1ULL << 5))) + \
  15. (!!((w) & (1ULL << 6))) + \
  16. (!!((w) & (1ULL << 7)))))
  17. #define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 ))
  18. #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
  19. #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
  20. /*
  21. * Generic interface.
  22. */
  23. #define hweight8(w) (__builtin_constant_p(w) ? __const_hweight8(w) : __arch_hweight8(w))
  24. #define hweight16(w) (__builtin_constant_p(w) ? __const_hweight16(w) : __arch_hweight16(w))
  25. #define hweight32(w) (__builtin_constant_p(w) ? __const_hweight32(w) : __arch_hweight32(w))
  26. #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
  27. /*
  28. * Interface for known constant arguments
  29. */
  30. #define HWEIGHT8(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight8(w))
  31. #define HWEIGHT16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight16(w))
  32. #define HWEIGHT32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight32(w))
  33. #define HWEIGHT64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight64(w))
  34. /*
  35. * Type invariant interface to the compile time constant hweight functions.
  36. */
  37. #define HWEIGHT(w) HWEIGHT64((u64)w)
  38. #endif /* _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_ */