Files
android/arch/x86/lib/hweight.S
T
threeeye bc1d038eac REVVL 6 Pro kernel bring-up: full working tree snapshot (2026-09-12)
Squashed backup commit (no shallow-clone history issues) of
xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2 branch, upstream
commit 9eece662e) plus all fixes applied to get everpal_defconfig building
clean against a modern (GCC 15.2.0) toolchain -- see the previous commit
message on the lineage-23.2 branch (also in this repo history is not
available here since this is a squashed snapshot; full incremental history
lives in the local DL380 checkout and the upstream GitHub remote).

Upstream: https://github.com/xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2)
2026-09-12 13:36:46 +00:00

84 lines
2.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/linkage.h>
#include <asm/export.h>
#include <asm/asm.h>
/*
* unsigned int __sw_hweight32(unsigned int w)
* %rdi: w
*/
ENTRY(__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
ENDPROC(__sw_hweight32)
EXPORT_SYMBOL(__sw_hweight32)
ENTRY(__sw_hweight64)
#ifdef CONFIG_X86_64
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
#else /* CONFIG_X86_32 */
/* We're getting an u64 arg in (%eax,%edx): unsigned long hweight64(__u64 w) */
pushl %ecx
call __sw_hweight32
movl %eax, %ecx # stash away result
movl %edx, %eax # second part of input
call __sw_hweight32
addl %ecx, %eax # result
popl %ecx
ret
#endif
ENDPROC(__sw_hweight64)
EXPORT_SYMBOL(__sw_hweight64)