kernel/include/asm-generic/bitops/const_hweight.h

   1 #ifndef _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
   2 #define _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
   3
   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
  18 #define __const_hweight16(w) (__const_hweight8(w)  + __const_hweight8((w)  >> 8 ))
  19 #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
  20 #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
  21
  22 /*
  23  * Generic interface.
  24  */
  25 #define hweight8(w)  (__builtin_constant_p(w) ? __const_hweight8(w)  : __arch_hweight8(w))
  26 #define hweight16(w) (__builtin_constant_p(w) ? __const_hweight16(w) : __arch_hweight16(w))
  27 #define hweight32(w) (__builtin_constant_p(w) ? __const_hweight32(w) : __arch_hweight32(w))
  28 #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
  29
  30 /*
  31  * Interface for known constant arguments
  32  */
  33 #define HWEIGHT8(w)  (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight8(w))
  34 #define HWEIGHT16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight16(w))
  35 #define HWEIGHT32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight32(w))
  36 #define HWEIGHT64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight64(w))
  37
  38 /*
  39  * Type invariant interface to the compile time constant hweight functions.
  40  */
  41 #define HWEIGHT(w)   HWEIGHT64((u64)w)
  42
  43 #endif /* _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_ */