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

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