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 # 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 36 SYM_FUNC_END(__sw_hweight32) 37 EXPORT_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 44 SYM_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 73 SYM_FUNC_END(__sw_hweight64) 74 EXPORT_SYMBOL(__sw_hweight64) 75 #endif
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