1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/bitops.h>
4#include <asm/types.h>
5
6/**
7 * hweightN - returns the hamming weight of a N-bit word
8 * @x: the word to weigh
9 *
10 * The Hamming Weight of a number is the total number of bits set in it.
11 */
12
13unsigned int __sw_hweight32(unsigned int w)
14{
15#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
16	w -= (w >> 1) & 0x55555555;
17	w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);
18	w =  (w + (w >> 4)) & 0x0f0f0f0f;
19	return (w * 0x01010101) >> 24;
20#else
21	unsigned int res = w - ((w >> 1) & 0x55555555);
22	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
23	res = (res + (res >> 4)) & 0x0F0F0F0F;
24	res = res + (res >> 8);
25	return (res + (res >> 16)) & 0x000000FF;
26#endif
27}
28EXPORT_SYMBOL(__sw_hweight32);
29
30unsigned int __sw_hweight16(unsigned int w)
31{
32	unsigned int res = w - ((w >> 1) & 0x5555);
33	res = (res & 0x3333) + ((res >> 2) & 0x3333);
34	res = (res + (res >> 4)) & 0x0F0F;
35	return (res + (res >> 8)) & 0x00FF;
36}
37EXPORT_SYMBOL(__sw_hweight16);
38
39unsigned int __sw_hweight8(unsigned int w)
40{
41	unsigned int res = w - ((w >> 1) & 0x55);
42	res = (res & 0x33) + ((res >> 2) & 0x33);
43	return (res + (res >> 4)) & 0x0F;
44}
45EXPORT_SYMBOL(__sw_hweight8);
46
47unsigned long __sw_hweight64(__u64 w)
48{
49#if BITS_PER_LONG == 32
50	return __sw_hweight32((unsigned int)(w >> 32)) +
51	       __sw_hweight32((unsigned int)w);
52#elif BITS_PER_LONG == 64
53#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
54	w -= (w >> 1) & 0x5555555555555555ul;
55	w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
56	w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
57	return (w * 0x0101010101010101ul) >> 56;
58#else
59	__u64 res = w - ((w >> 1) & 0x5555555555555555ul);
60	res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
61	res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
62	res = res + (res >> 8);
63	res = res + (res >> 16);
64	return (res + (res >> 32)) & 0x00000000000000FFul;
65#endif
66#endif
67}
68EXPORT_SYMBOL(__sw_hweight64);
69