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 */
11 SYM_FUNC_START(__sw_hweight32)
12
13 #ifdef CONFIG_X86_64
14 movl %edi, %eax
15 #endif
16 __ASM_SIZE(push,) %__ASM_REG(dx)
17 movl %eax, %edx
18 shrl %edx
19 andl $0x55555555, %edx
20 subl %edx, %eax
21
22 movl %eax, %edx
23 shrl $2, %eax
24 andl $0x33333333, %edx
25 andl $0x33333333, %eax
26 addl %edx, %eax
27
28 movl %eax, %edx
29 shrl $4, %edx
30 addl %edx, %eax
31 andl $0x0f0f0f0f, %eax
32 imull $0x01010101, %eax, %eax
33 shrl $24, %eax
34 __ASM_SIZE(pop,) %__ASM_REG(dx)
35 RET
36 SYM_FUNC_END(__sw_hweight32)
37 EXPORT_SYMBOL(__sw_hweight32)
38
39 /*
40 * No 32-bit variant, because it's implemented
41 * on top of __arch_hweight32():
42 */
43 #ifdef CONFIG_X86_64
44 SYM_FUNC_START(__sw_hweight64)
45 pushq %rdi
46 pushq %rdx
47
48 movq %rdi, %rdx
49 movabsq $0x5555555555555555, %rax
50 shrq %rdx
51 andq %rdx, %rax
52 movabsq $0x3333333333333333, %rdx
53 subq %rax, %rdi
54
55 movq %rdi, %rax
56 shrq $2, %rdi
57 andq %rdx, %rax
58 andq %rdi, %rdx
59 addq %rdx, %rax
60
61 movq %rax, %rdx
62 shrq $4, %rdx
63 addq %rdx, %rax
64 movabsq $0x0f0f0f0f0f0f0f0f, %rdx
65 andq %rdx, %rax
66 movabsq $0x0101010101010101, %rdx
67 imulq %rdx, %rax
68 shrq $56, %rax
69
70 popq %rdx
71 popq %rdi
72 RET
73 SYM_FUNC_END(__sw_hweight64)
74 EXPORT_SYMBOL(__sw_hweight64)
75 #endif
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