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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/sh/lib/strlen.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/* $Id: strlen.S,v 1.2 2001/06/29 14:07:15 gniibe Exp $

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 *

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 * "strlen" implementation of SuperH

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 *

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 * Copyright (C) 1999  Kaz Kojima

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 *

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 */

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/* size_t strlen (const char *s)  */

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#include <linux/linkage.h>

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ENTRY(strlen)

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	mov	r4,r0

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	and	#3,r0

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	tst	r0,r0

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	bt/s	1f

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	 mov	#0,r2

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	add	#-1,r0

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	shll2	r0

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	shll	r0

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	braf	r0

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	 nop

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	mov.b	@r4+,r1

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	tst	r1,r1

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	bt	8f

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	add	#1,r2

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	mov.b	@r4+,r1

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	tst	r1,r1

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	bt	8f

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	add	#1,r2

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	mov.b	@r4+,r1

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	tst	r1,r1

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	bt	8f

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	add	#1,r2

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1:

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	mov	#0,r3

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2:

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	mov.l	@r4+,r1

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	cmp/str	r3,r1

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	bf/s	2b

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	 add	#4,r2

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	add	#-4,r2

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#ifndef __LITTLE_ENDIAN__

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	swap.b	r1,r1

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	swap.w	r1,r1

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	swap.b	r1,r1

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#endif

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	extu.b	r1,r0

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	tst	r0,r0

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	bt/s	8f

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	 shlr8	r1

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	add	#1,r2

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	extu.b	r1,r0

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	tst	r0,r0

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	bt/s	8f

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	 shlr8	r1

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	add	#1,r2

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	extu.b	r1,r0

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	tst	r0,r0

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	bt	8f

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	add	#1,r2

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8:

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	rts

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	 mov	r2,r0

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