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

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/*

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 *  linux/arch/arm/lib/copypage.S

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 *

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 *  Copyright (C) 1995-1999 Russell King

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 *

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 *  ASM optimised string functions

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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#include <asm/asm-offsets.h>

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#include <asm/cache.h>

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#define COPY_COUNT (PAGE_SZ / (2 * L1_CACHE_BYTES) PLD( -1 ))

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		.text

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		.align	5

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/*

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 * StrongARM optimised copy_page routine

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 * now 1.78bytes/cycle, was 1.60 bytes/cycle (50MHz bus -> 89MB/s)

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 * Note that we probably achieve closer to the 100MB/s target with

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 * the core clock switching.

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 */

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ENTRY(copy_page)

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		stmfd	sp!, {r4, lr}			@	2

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	PLD(	pld	[r1, #0]		)

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	PLD(	pld	[r1, #L1_CACHE_BYTES]		)

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		mov	r2, #COPY_COUNT			@	1

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		ldmia	r1!, {r3, r4, ip, lr}		@	4+1

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1:	PLD(	pld	[r1, #2 * L1_CACHE_BYTES])

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	PLD(	pld	[r1, #3 * L1_CACHE_BYTES])

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2:

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	.rept	(2 * L1_CACHE_BYTES / 16 - 1)

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		stmia	r0!, {r3, r4, ip, lr}		@	4

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		ldmia	r1!, {r3, r4, ip, lr}		@	4

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	.endr

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		subs	r2, r2, #1			@	1

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		stmia	r0!, {r3, r4, ip, lr}		@	4

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		ldmiagt	r1!, {r3, r4, ip, lr}		@	4

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		bgt	1b				@	1

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	PLD(	ldmiaeq r1!, {r3, r4, ip, lr}	)

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	PLD(	beq	2b			)

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		ldmfd	sp!, {r4, pc}			@	3

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ENDPROC(copy_page)

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