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path: root/src/arch/arm64/memmove.S
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/* SPDX-License-Identifier: GPL-2.0-only */

#include <arch/asm.h>
/*
 * Move a buffer from src to test (alignment handled by the hardware).
 * If dest <= src, call memcpy, otherwise copy in reverse order.
 *
 * Parameters:
 *	x0 - dest
 *	x1 - src
 *	x2 - n
 * Returns:
 *	x0 - dest
 */
ENTRY(memmove)
	cmp	x0, x1
	b.ls	memcpy
	add	x4, x0, x2
	add	x1, x1, x2
	subs	x2, x2, #8
	b.mi	2f
1:	ldr	x3, [x1, #-8]!
	subs	x2, x2, #8
	str	x3, [x4, #-8]!
	b.pl	1b
2:	adds	x2, x2, #4
	b.mi	3f
	ldr	w3, [x1, #-4]!
	sub	x2, x2, #4
	str	w3, [x4, #-4]!
3:	adds	x2, x2, #2
	b.mi	4f
	ldrh	w3, [x1, #-2]!
	sub	x2, x2, #2
	strh	w3, [x4, #-2]!
4:	adds	x2, x2, #1
	b.mi	5f
	ldrb	w3, [x1, #-1]
	strb	w3, [x4, #-1]
5:	ret
ENDPROC(memmove)