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- /* SPDX-License-Identifier: GPL-2.0 */
- #include <linux/export.h>
- #include <linux/linkage.h>
- #include <asm/asm.h>
- /*
- * unsigned int __sw_hweight32(unsigned int w)
- * %rdi: w
- */
- SYM_FUNC_START(__sw_hweight32)
- #ifdef CONFIG_X86_64
- movl %edi, %eax # w
- #endif
- __ASM_SIZE(push,) %__ASM_REG(dx)
- movl %eax, %edx # w -> t
- shrl %edx # t >>= 1
- andl $0x55555555, %edx # t &= 0x55555555
- subl %edx, %eax # w -= t
- movl %eax, %edx # w -> t
- shrl $2, %eax # w_tmp >>= 2
- andl $0x33333333, %edx # t &= 0x33333333
- andl $0x33333333, %eax # w_tmp &= 0x33333333
- addl %edx, %eax # w = w_tmp + t
- movl %eax, %edx # w -> t
- shrl $4, %edx # t >>= 4
- addl %edx, %eax # w_tmp += t
- andl $0x0f0f0f0f, %eax # w_tmp &= 0x0f0f0f0f
- imull $0x01010101, %eax, %eax # w_tmp *= 0x01010101
- shrl $24, %eax # w = w_tmp >> 24
- __ASM_SIZE(pop,) %__ASM_REG(dx)
- RET
- SYM_FUNC_END(__sw_hweight32)
- EXPORT_SYMBOL(__sw_hweight32)
- /*
- * No 32-bit variant, because it's implemented as an inline wrapper
- * on top of __arch_hweight32():
- */
- #ifdef CONFIG_X86_64
- SYM_FUNC_START(__sw_hweight64)
- pushq %rdi
- pushq %rdx
- movq %rdi, %rdx # w -> t
- movabsq $0x5555555555555555, %rax
- shrq %rdx # t >>= 1
- andq %rdx, %rax # t &= 0x5555555555555555
- movabsq $0x3333333333333333, %rdx
- subq %rax, %rdi # w -= t
- movq %rdi, %rax # w -> t
- shrq $2, %rdi # w_tmp >>= 2
- andq %rdx, %rax # t &= 0x3333333333333333
- andq %rdi, %rdx # w_tmp &= 0x3333333333333333
- addq %rdx, %rax # w = w_tmp + t
- movq %rax, %rdx # w -> t
- shrq $4, %rdx # t >>= 4
- addq %rdx, %rax # w_tmp += t
- movabsq $0x0f0f0f0f0f0f0f0f, %rdx
- andq %rdx, %rax # w_tmp &= 0x0f0f0f0f0f0f0f0f
- movabsq $0x0101010101010101, %rdx
- imulq %rdx, %rax # w_tmp *= 0x0101010101010101
- shrq $56, %rax # w = w_tmp >> 56
- popq %rdx
- popq %rdi
- RET
- SYM_FUNC_END(__sw_hweight64)
- EXPORT_SYMBOL(__sw_hweight64)
- #endif
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