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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arc/lib/strcmp-archs.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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/*

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 * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)

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 */

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#include <linux/linkage.h>

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ENTRY_CFI(strcmp)

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	or	r2, r0, r1

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	bmsk_s	r2, r2, 1

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	brne	r2, 0, @.Lcharloop

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;;; s1 and s2 are word aligned

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	ld.ab	r2, [r0, 4]

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	mov_s	r12, 0x01010101

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	ror	r11, r12

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	.align  4

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.LwordLoop:

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	ld.ab	r3, [r1, 4]

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	;; Detect NULL char in str1

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	sub	r4, r2, r12

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	ld.ab	r5, [r0, 4]

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	bic	r4, r4, r2

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	and	r4, r4, r11

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	brne.d.nt	r4, 0, .LfoundNULL

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	;; Check if the read locations are the same

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	cmp	r2, r3

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	beq.d	.LwordLoop

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	mov.eq	r2, r5

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	;; A match is found, spot it out

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#ifdef __LITTLE_ENDIAN__

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	swape	r3, r3

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	mov_s	r0, 1

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	swape	r2, r2

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#else

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	mov_s	r0, 1

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#endif

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	cmp_s	r2, r3

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	j_s.d	[blink]

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	bset.lo	r0, r0, 31

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	.align 4

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.LfoundNULL:

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#ifdef __BIG_ENDIAN__

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	swape	r4, r4

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	swape	r2, r2

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	swape	r3, r3

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#endif

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	;; Find null byte

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	ffs	r0, r4

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	bmsk	r2, r2, r0

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	bmsk	r3, r3, r0

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	swape	r2, r2

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	swape	r3, r3

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	;; make the return value

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	sub.f	r0, r2, r3

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	mov.hi	r0, 1

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	j_s.d	[blink]

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	bset.lo	r0, r0, 31

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	.align 4

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.Lcharloop:

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	ldb.ab	r2, [r0, 1]

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	ldb.ab	r3, [r1, 1]

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	nop

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	breq	r2, 0, .Lcmpend

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	breq	r2, r3, .Lcharloop

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	.align 4

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.Lcmpend:

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	j_s.d	[blink]

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	sub	r0, r2, r3

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END_CFI(strcmp)

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