Differential D15483 Diff 42709 sys/amd64/amd64/support.S

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sys/amd64/amd64/support.S

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jne 1b		jne 1b
sfence		sfence
POP_FRAME_POINTER		POP_FRAME_POINTER
ret		ret
END(sse2_pagezero)		END(sse2_pagezero)

ENTRY(bcmp)		ENTRY(bcmp)
PUSH_FRAME_POINTER		PUSH_FRAME_POINTER
		/*
		* If the length is less than 8, skip right to the 1-byte
		* comparisons.
		*/
		cmpq $8,%rdx
		jb 5f

		/*
		* If the length is greater than 64, we'll use repe cmpsq
		* rather than our own loop.
		*/
		cmpq $64,%rdx
		ja 4f

		/*
		* Do 8-byte comparisons in a loop.
		*
		* In this section, we use these register assignments:
		* %r9: Count of 8-byte comparisons.
		* %ecx: Current 8-byte comparison index.
		* %rdx: Number of remaining 1-byte comparisons.
		*/
		movq %rdx,%r9
		shrq $3,%r9
		andq $7,%rdx
		xor %ecx,%ecx
		10:
		movq (%rdi,%rcx,8),%r8
		cmpq (%rsi,%rcx,8),%r8
		jne 3f
		addq $0x1,%rcx
		cmpq %rcx,%r9
		jne 10b

		/*
		* If any bytes remain, we need to increment %rdi and %rsi in
		* preparation for the 1-byte comparisons.
		*/
test %rdx,%rdx		test %rdx,%rdx
je 1f		je 1f
cmpq $64,%rdx		shlq $3,%rcx
jg 4f		addq %rcx,%rsi
		addq %rcx,%rdi
		jmp 6f

		5:
		/* Check for 0 length. */
		test %rdx,%rdx
		je 1f

		6:
		/* Mop up remaining bytes with 1-byte comparisons. */
xor %ecx,%ecx		xor %ecx,%ecx
2:		2:
movzbl (%rdi,%rcx,1),%eax		movzbl (%rdi,%rcx,1),%eax
movzbl (%rsi,%rcx,1),%r8d		movzbl (%rsi,%rcx,1),%r8d
cmp %r8b,%al		cmp %r8b,%al
jne 3f		jne 3f
add $0x1,%rcx		add $0x1,%rcx
cmp %rcx,%rdx		cmp %rcx,%rdx
jne 2b		jne 2b
1:		1:
		/* The memory matches. */
xor %eax,%eax		xor %eax,%eax
POP_FRAME_POINTER		POP_FRAME_POINTER
retq		retq
3:		3:
		/* The memory is different. */
mov $1,%eax		mov $1,%eax
POP_FRAME_POINTER		POP_FRAME_POINTER
retq		retq
4:		4:
		/*
		* Use repe cmpsq to compare long 8-byte strings. Then, mop
		* up remaining bytes with a small loop of 1-byte comparisons.
		*/
movq %rdx,%rcx		movq %rdx,%rcx
shrq $3,%rcx		shrq $3,%rcx
repe		repe
cmpsq		cmpsq
jne 5f		jne 3b
		andq $7,%rdx
movq %rdx,%rcx		jmp 5b
andq $7,%rcx
repe
cmpsb
5:
setne %al
movsbl %al,%eax
POP_FRAME_POINTER
ret
END(bcmp)		END(bcmp)

/*		/*
* bcopy(src, dst, cnt)		* bcopy(src, dst, cnt)
* rdi, rsi, rdx		* rdi, rsi, rdx
* ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800		* ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
*/		*/
ENTRY(bcopy)		ENTRY(bcopy)
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