1/* SPDX-License-Identifier: GPL-2.0 */
2#include <linux/export.h>
3#include <linux/linkage.h>
4
5#include <asm/asm.h>
6
7/*
8 * unsigned int __sw_hweight32(unsigned int w)
9 * %rdi: w
10 */
11SYM_FUNC_START(__sw_hweight32)
12
13#ifdef CONFIG_X86_64
14	movl %edi, %eax				# w
15#endif
16	__ASM_SIZE(push,) %__ASM_REG(dx)
17	movl %eax, %edx				# w -> t
18	shrl %edx				# t >>= 1
19	andl $0x55555555, %edx			# t &= 0x55555555
20	subl %edx, %eax				# w -= t
21
22	movl %eax, %edx				# w -> t
23	shrl $2, %eax				# w_tmp >>= 2
24	andl $0x33333333, %edx			# t	&= 0x33333333
25	andl $0x33333333, %eax			# w_tmp &= 0x33333333
26	addl %edx, %eax				# w = w_tmp + t
27
28	movl %eax, %edx				# w -> t
29	shrl $4, %edx				# t >>= 4
30	addl %edx, %eax				# w_tmp += t
31	andl  $0x0f0f0f0f, %eax			# w_tmp &= 0x0f0f0f0f
32	imull $0x01010101, %eax, %eax		# w_tmp *= 0x01010101
33	shrl $24, %eax				# w = w_tmp >> 24
34	__ASM_SIZE(pop,) %__ASM_REG(dx)
35	RET
36SYM_FUNC_END(__sw_hweight32)
37EXPORT_SYMBOL(__sw_hweight32)
38
39/*
40 * No 32-bit variant, because it's implemented as an inline wrapper
41 * on top of __arch_hweight32():
42 */
43#ifdef CONFIG_X86_64
44SYM_FUNC_START(__sw_hweight64)
45	pushq   %rdi
46	pushq   %rdx
47
48	movq    %rdi, %rdx                      # w -> t
49	movabsq $0x5555555555555555, %rax
50	shrq    %rdx                            # t >>= 1
51	andq    %rdx, %rax                      # t &= 0x5555555555555555
52	movabsq $0x3333333333333333, %rdx
53	subq    %rax, %rdi                      # w -= t
54
55	movq    %rdi, %rax                      # w -> t
56	shrq    $2, %rdi                        # w_tmp >>= 2
57	andq    %rdx, %rax                      # t     &= 0x3333333333333333
58	andq    %rdi, %rdx                      # w_tmp &= 0x3333333333333333
59	addq    %rdx, %rax                      # w = w_tmp + t
60
61	movq    %rax, %rdx                      # w -> t
62	shrq    $4, %rdx                        # t >>= 4
63	addq    %rdx, %rax                      # w_tmp += t
64	movabsq $0x0f0f0f0f0f0f0f0f, %rdx
65	andq    %rdx, %rax                      # w_tmp &= 0x0f0f0f0f0f0f0f0f
66	movabsq $0x0101010101010101, %rdx
67	imulq   %rdx, %rax                      # w_tmp *= 0x0101010101010101
68	shrq    $56, %rax                       # w = w_tmp >> 56
69
70	popq    %rdx
71	popq    %rdi
72	RET
73SYM_FUNC_END(__sw_hweight64)
74EXPORT_SYMBOL(__sw_hweight64)
75#endif
76