diff options
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/Makefile | 5 | ||||
| -rw-r--r-- | arch/x86/lib/hweight.S | 79 |
2 files changed, 83 insertions, 1 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 12a34d15b648..7f46ea66eeb6 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -2,6 +2,9 @@ # Makefile for x86 specific library files. # +# Produces uninteresting flaky coverage. +KCOV_INSTRUMENT_delay.o := n + inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk inat_tables_maps = $(srctree)/arch/x86/lib/x86-opcode-map.txt quiet_cmd_inat_tables = GEN $@ @@ -23,7 +26,7 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o lib-$(CONFIG_RETPOLINE) += retpoline.o -obj-y += msr.o msr-reg.o msr-reg-export.o +obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o ifeq ($(CONFIG_X86_32),y) obj-y += atomic64_32.o diff --git a/arch/x86/lib/hweight.S b/arch/x86/lib/hweight.S new file mode 100644 index 000000000000..8a602a1e404a --- /dev/null +++ b/arch/x86/lib/hweight.S @@ -0,0 +1,79 @@ +#include <linux/linkage.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) + +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) |