LXR linux/include/asm-generic/bitops/const

   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_ */
  44