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       ( (!!((w) & (1ULL << 0))) +       \
   9         (!!((w) & (1ULL << 1))) +       \
  10         (!!((w) & (1ULL << 2))) +       \
  11         (!!((w) & (1ULL << 3))) +       \
  12         (!!((w) & (1ULL << 4))) +       \
  13         (!!((w) & (1ULL << 5))) +       \
  14         (!!((w) & (1ULL << 6))) +       \
  15         (!!((w) & (1ULL << 7))) )
  16
  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 /*
  22  * Generic interface.
  23  */
  24 #define hweight8(w)  (__builtin_constant_p(w) ? __const_hweight8(w)  : __arch_hweight8(w))
  25 #define hweight16(w) (__builtin_constant_p(w) ? __const_hweight16(w) : __arch_hweight16(w))
  26 #define hweight32(w) (__builtin_constant_p(w) ? __const_hweight32(w) : __arch_hweight32(w))
  27 #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
  28
  29 /*
  30  * Interface for known constant arguments
  31  */
  32 #define HWEIGHT8(w)  (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight8(w))
  33 #define HWEIGHT16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight16(w))
  34 #define HWEIGHT32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight32(w))
  35 #define HWEIGHT64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight64(w))
  36
  37 /*
  38  * Type invariant interface to the compile time constant hweight functions.
  39  */
  40 #define HWEIGHT(w)   HWEIGHT64((u64)w)
  41
  42 #endif /* _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_ */