include/asm-generic/bitops/const_hweight.h

   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 /*
   6  * Compile time versions of __arch_hweightN()
   7  */
   8 #define __const_hweight8(w)             \
   9         ((unsigned int)                 \
  10          ((!!((w) & (1ULL << 0))) +     \
  11           (!!((w) & (1ULL << 1))) +     \
  12           (!!((w) & (1ULL << 2))) +     \
  13           (!!((w) & (1ULL << 3))) +     \
  14           (!!((w) & (1ULL << 4))) +     \
  15           (!!((w) & (1ULL << 5))) +     \
  16           (!!((w) & (1ULL << 6))) +     \
  17           (!!((w) & (1ULL << 7)))))
  18
  19 #define __const_hweight16(w) (__const_hweight8(w)  + __const_hweight8((w)  >> 8 ))
  20 #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
  21 #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
  22
  23 /*
  24  * Generic interface.
  25  */
  26 #define hweight8(w)  (__builtin_constant_p(w) ? __const_hweight8(w)  : __arch_hweight8(w))
  27 #define hweight16(w) (__builtin_constant_p(w) ? __const_hweight16(w) : __arch_hweight16(w))
  28 #define hweight32(w) (__builtin_constant_p(w) ? __const_hweight32(w) : __arch_hweight32(w))
  29 #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
  30
  31 /*
  32  * Interface for known constant arguments
  33  */
  34 #define HWEIGHT8(w)  (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight8(w))
  35 #define HWEIGHT16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight16(w))
  36 #define HWEIGHT32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight32(w))
  37 #define HWEIGHT64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight64(w))
  38
  39 /*
  40  * Type invariant interface to the compile time constant hweight functions.
  41  */
  42 #define HWEIGHT(w)   HWEIGHT64((u64)w)
  43
  44 #endif /* _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_ */