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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arm/lib/io-readsw-armv4.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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/*

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 *  linux/arch/arm/lib/io-readsw-armv4.S

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 *

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 *  Copyright (C) 1995-2000 Russell King

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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		.macro	pack, rd, hw1, hw2

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#ifndef __ARMEB__

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		orr	\rd, \hw1, \hw2, lsl #16

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#else

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		orr	\rd, \hw2, \hw1, lsl #16

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#endif

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		.endm

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.Linsw_align:	movs	ip, r1, lsl #31

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		bne	.Linsw_noalign

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		ldrh	ip, [r0]

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		sub	r2, r2, #1

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		strh	ip, [r1], #2

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ENTRY(__raw_readsw)

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		teq	r2, #0

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		reteq	lr

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		tst	r1, #3

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		bne	.Linsw_align

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		stmfd	sp!, {r4, r5, lr}

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		subs	r2, r2, #8

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		bmi	.Lno_insw_8

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.Linsw_8_lp:	ldrh	r3, [r0]

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		ldrh	r4, [r0]

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		pack	r3, r3, r4

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		ldrh	r4, [r0]

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		ldrh	r5, [r0]

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		pack	r4, r4, r5

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		ldrh	r5, [r0]

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		ldrh	ip, [r0]

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		pack	r5, r5, ip

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		ldrh	ip, [r0]

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		ldrh	lr, [r0]

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		pack	ip, ip, lr

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		subs	r2, r2, #8

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		stmia	r1!, {r3 - r5, ip}

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		bpl	.Linsw_8_lp

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.Lno_insw_8:	tst	r2, #4

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		beq	.Lno_insw_4

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		ldrh	r3, [r0]

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		ldrh	r4, [r0]

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		pack	r3, r3, r4

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		ldrh	r4, [r0]

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		ldrh	ip, [r0]

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		pack	r4, r4, ip

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		stmia	r1!, {r3, r4}

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.Lno_insw_4:	movs	r2, r2, lsl #31

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		bcc	.Lno_insw_2

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		ldrh	r3, [r0]

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		ldrh	ip, [r0]

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		pack	r3, r3, ip

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		str	r3, [r1], #4

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.Lno_insw_2:	ldrhne	r3, [r0]

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		strhne	r3, [r1]

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		ldmfd	sp!, {r4, r5, pc}

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#ifdef __ARMEB__

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#define _BE_ONLY_(code...)	code

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#define _LE_ONLY_(code...)

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#define push_hbyte0		lsr #8

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#define pull_hbyte1		lsl #24

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#else

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#define _BE_ONLY_(code...)

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#define _LE_ONLY_(code...) code

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#define push_hbyte0		lsl #24

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#define pull_hbyte1		lsr #8

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#endif

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.Linsw_noalign:	stmfd	sp!, {r4, lr}

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		ldrbcc	ip, [r1, #-1]!

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		bcc	1f

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		ldrh	ip, [r0]

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		sub	r2, r2, #1

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   _BE_ONLY_(	mov	ip, ip, ror #8		)

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		strb	ip, [r1], #1

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   _LE_ONLY_(	mov	ip, ip, lsr #8		)

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   _BE_ONLY_(	mov	ip, ip, lsr #24		)

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1:		subs	r2, r2, #2

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		bmi	3f

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   _BE_ONLY_(	mov	ip, ip, lsl #24		)

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2:		ldrh	r3, [r0]

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		ldrh	r4, [r0]

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		subs	r2, r2, #2

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		orr	ip, ip, r3, lsl #8

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		orr	ip, ip, r4, push_hbyte0

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		str	ip, [r1], #4

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		mov	ip, r4, pull_hbyte1

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		bpl	2b

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   _BE_ONLY_(	mov	ip, ip, lsr #24		)

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3:		tst	r2, #1

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		strb	ip, [r1], #1

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		ldrhne	ip, [r0]

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   _BE_ONLY_(	movne	ip, ip, ror #8		)

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		strbne	ip, [r1], #1

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   _LE_ONLY_(	movne	ip, ip, lsr #8		)

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   _BE_ONLY_(	movne	ip, ip, lsr #24		)

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		strbne	ip, [r1]

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		ldmfd	sp!, {r4, pc}

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ENDPROC(__raw_readsw)

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