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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/csky/abiv2/memset.S
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/* SPDX-License-Identifier: GPL-2.0 */

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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

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#include <linux/linkage.h>

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#include "sysdep.h"

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	.weak memset

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ENTRY(__memset)

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ENTRY(memset)

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	/* Test if len less than 4 bytes.  */

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	mov	r12, r0

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	cmplti	r2, 8

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	bt	.L_set_by_byte

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	andi	r13, r0, 3

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	movi	r19, 4

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	/* Test if dest is not 4 bytes aligned.  */

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	bnez	r13, .L_dest_not_aligned

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	/* Hardware can handle unaligned access directly.  */

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.L_dest_aligned:

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        zextb   r3, r1

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        lsli    r1, 8

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        or      r1, r3

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        lsli    r3, r1, 16

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        or      r3, r1

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	/* If dest is aligned, then copy.  */

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	zext	r18, r2, 31, 4

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	/* Test if len less than 16 bytes.  */

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	bez	r18, .L_len_less_16bytes

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	LABLE_ALIGN

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.L_len_larger_16bytes:

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	stw	r3, (r0, 0)

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	stw	r3, (r0, 4)

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	stw	r3, (r0, 8)

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	stw	r3, (r0, 12)

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	PRE_BNEZAD (r18)

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	addi	r0, 16

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	BNEZAD (r18, .L_len_larger_16bytes)

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.L_len_less_16bytes:

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	zext	r18, r2, 3, 2

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	andi	r2, 3

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	bez	r18, .L_set_by_byte

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.L_len_less_16bytes_loop:

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	stw	r3, (r0, 0)

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	PRE_BNEZAD (r18)

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	addi	r0, 4

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	BNEZAD (r18, .L_len_less_16bytes_loop)

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	/* Test if len less than 4 bytes.  */

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.L_set_by_byte:

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	zext	r18, r2, 2, 0

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	bez	r18, .L_return

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.L_set_by_byte_loop:

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	stb	r1, (r0, 0)

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	PRE_BNEZAD (r18)

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	addi	r0, 1

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	BNEZAD (r18, .L_set_by_byte_loop)

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.L_return:

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	mov	r0, r12

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	rts

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	/* If dest is not aligned, just set some bytes makes the dest

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	   align.  */

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.L_dest_not_aligned:

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	sub	r13, r19, r13

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	sub	r2, r13

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.L_dest_not_aligned_loop:

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	/* Makes the dest align.  */

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	stb	r1, (r0, 0)

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	PRE_BNEZAD (r13)

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	addi	r0, 1

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	BNEZAD (r13, .L_dest_not_aligned_loop)

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	cmplti	r2, 8

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	bt	.L_set_by_byte

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	/* Check whether the src is aligned.  */

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	jbr	.L_dest_aligned

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ENDPROC(memset)

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ENDPROC(__memset)

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