xref: /linux/include/asm-generic/bitops/const_hweight.h (revision 96ac6d435100450f0565708d9b885ea2a7400e0a)
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_ */
45