asm-generic/bitops/const_hweight.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
0003 #define _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_
0004
0005 /*
0006  * Compile time versions of __arch_hweightN()
0007  */
0008 #define __const_hweight8(w)     \
0009     ((unsigned int)         \
0010      ((!!((w) & (1ULL << 0))) + \
0011       (!!((w) & (1ULL << 1))) + \
0012       (!!((w) & (1ULL << 2))) + \
0013       (!!((w) & (1ULL << 3))) + \
0014       (!!((w) & (1ULL << 4))) + \
0015       (!!((w) & (1ULL << 5))) + \
0016       (!!((w) & (1ULL << 6))) + \
0017       (!!((w) & (1ULL << 7)))))
0018
0019 #define __const_hweight16(w) (__const_hweight8(w)  + __const_hweight8((w)  >> 8 ))
0020 #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
0021 #define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32))
0022
0023 /*
0024  * Generic interface.
0025  */
0026 #define hweight8(w)  (__builtin_constant_p(w) ? __const_hweight8(w)  : __arch_hweight8(w))
0027 #define hweight16(w) (__builtin_constant_p(w) ? __const_hweight16(w) : __arch_hweight16(w))
0028 #define hweight32(w) (__builtin_constant_p(w) ? __const_hweight32(w) : __arch_hweight32(w))
0029 #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w))
0030
0031 /*
0032  * Interface for known constant arguments
0033  */
0034 #define HWEIGHT8(w)  (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight8(w))
0035 #define HWEIGHT16(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight16(w))
0036 #define HWEIGHT32(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight32(w))
0037 #define HWEIGHT64(w) (BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + __const_hweight64(w))
0038
0039 /*
0040  * Type invariant interface to the compile time constant hweight functions.
0041  */
0042 #define HWEIGHT(w)   HWEIGHT64((u64)w)
0043
0044 #endif /* _ASM_GENERIC_BITOPS_CONST_HWEIGHT_H_ */