[linux-2.6-block.git] / arch / x86 / lib / hweight.S

#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   %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
	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)
Commit	Line	Data
f5967101 BP	1	#include <linux/linkage.h>
	2
	3	#include <asm/asm.h>
	4
	5	/*
	6	* unsigned int __sw_hweight32(unsigned int w)
	7	* %rdi: w
	8	*/
	9	ENTRY(__sw_hweight32)
	10
	11	#ifdef CONFIG_X86_64
	12	movl %edi, %eax # w
	13	#endif
	14	__ASM_SIZE(push,) %__ASM_REG(dx)
	15	movl %eax, %edx # w -> t
	16	shrl %edx # t >>= 1
	17	andl $0x55555555, %edx # t &= 0x55555555
	18	subl %edx, %eax # w -= t
	19
	20	movl %eax, %edx # w -> t
	21	shrl $2, %eax # w_tmp >>= 2
	22	andl $0x33333333, %edx # t &= 0x33333333
	23	andl $0x33333333, %eax # w_tmp &= 0x33333333
	24	addl %edx, %eax # w = w_tmp + t
	25
	26	movl %eax, %edx # w -> t
	27	shrl $4, %edx # t >>= 4
	28	addl %edx, %eax # w_tmp += t
	29	andl $0x0f0f0f0f, %eax # w_tmp &= 0x0f0f0f0f
	30	imull $0x01010101, %eax, %eax # w_tmp *= 0x01010101
	31	shrl $24, %eax # w = w_tmp >> 24
	32	__ASM_SIZE(pop,) %__ASM_REG(dx)
	33	ret
	34	ENDPROC(__sw_hweight32)
	35
	36	ENTRY(__sw_hweight64)
	37	#ifdef CONFIG_X86_64
	38	pushq %rdx
	39
	40	movq %rdi, %rdx # w -> t
	41	movabsq $0x5555555555555555, %rax
	42	shrq %rdx # t >>= 1
	43	andq %rdx, %rax # t &= 0x5555555555555555
	44	movabsq $0x3333333333333333, %rdx
	45	subq %rax, %rdi # w -= t
	46
	47	movq %rdi, %rax # w -> t
	48	shrq $2, %rdi # w_tmp >>= 2
	49	andq %rdx, %rax # t &= 0x3333333333333333
	50	andq %rdi, %rdx # w_tmp &= 0x3333333333333333
	51	addq %rdx, %rax # w = w_tmp + t
	52
	53	movq %rax, %rdx # w -> t
	54	shrq $4, %rdx # t >>= 4
	55	addq %rdx, %rax # w_tmp += t
	56	movabsq $0x0f0f0f0f0f0f0f0f, %rdx
	57	andq %rdx, %rax # w_tmp &= 0x0f0f0f0f0f0f0f0f
	58	movabsq $0x0101010101010101, %rdx
	59	imulq %rdx, %rax # w_tmp *= 0x0101010101010101
	60	shrq $56, %rax # w = w_tmp >> 56
	61
	62	popq %rdx
	63	ret
	64	#else /* CONFIG_X86_32 */
65	/* We're getting an u64 arg in (%eax,%edx): unsigned long hweight64(__u64 w) */
66	pushl %ecx
67
68	call __sw_hweight32
69	movl %eax, %ecx # stash away result
70	movl %edx, %eax # second part of input
71	call __sw_hweight32
72	addl %ecx, %eax # result
73
74	popl %ecx
75	ret
76	#endif
77	ENDPROC(__sw_hweight64)