projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 94ea9c05 | 2 | #include <linux/export.h> |
| f5967101 BP |
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 | */ | |
| 6dcc5627 | 11 | SYM_FUNC_START(__sw_hweight32) |
| f5967101 BP |
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) | |
| f94909ce | 35 | RET |
| 6dcc5627 | 36 | SYM_FUNC_END(__sw_hweight32) |
| 784d5699 | 37 | EXPORT_SYMBOL(__sw_hweight32) |
| f5967101 | 38 | |
| ad424743 IM |
39 | /* |
| 40 | * No 32-bit variant, because it's implemented as an inline wrapper | |
| 41 | * on top of __arch_hweight32(): | |
| 42 | */ | |
| f5967101 | 43 | #ifdef CONFIG_X86_64 |
| ad424743 | 44 | SYM_FUNC_START(__sw_hweight64) |
| 65ea11ec | 45 | pushq %rdi |
| f5967101 BP |
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 | |
| 65ea11ec | 71 | popq %rdi |
| f94909ce | 72 | RET |
| 6dcc5627 | 73 | SYM_FUNC_END(__sw_hweight64) |
| 784d5699 | 74 | EXPORT_SYMBOL(__sw_hweight64) |
| ad424743 | 75 | #endif |