https://github.com/torvalds/linux
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Tip revision: 694d0d0bb2030d2e36df73e2d23d5770511dbc8d authored by Linus Torvalds on 15 August 2016, 02:11:36 UTC
Linux 4.8-rc2
Tip revision: 694d0d0
copy.S
/* ----------------------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

#include <linux/linkage.h>

/*
 * Memory copy routines
 */

	.code16
	.text

GLOBAL(memcpy)
	pushw	%si
	pushw	%di
	movw	%ax, %di
	movw	%dx, %si
	pushw	%cx
	shrw	$2, %cx
	rep; movsl
	popw	%cx
	andw	$3, %cx
	rep; movsb
	popw	%di
	popw	%si
	retl
ENDPROC(memcpy)

GLOBAL(memset)
	pushw	%di
	movw	%ax, %di
	movzbl	%dl, %eax
	imull	$0x01010101,%eax
	pushw	%cx
	shrw	$2, %cx
	rep; stosl
	popw	%cx
	andw	$3, %cx
	rep; stosb
	popw	%di
	retl
ENDPROC(memset)

GLOBAL(copy_from_fs)
	pushw	%ds
	pushw	%fs
	popw	%ds
	calll	memcpy
	popw	%ds
	retl
ENDPROC(copy_from_fs)

GLOBAL(copy_to_fs)
	pushw	%es
	pushw	%fs
	popw	%es
	calll	memcpy
	popw	%es
	retl
ENDPROC(copy_to_fs)

#if 0 /* Not currently used, but can be enabled as needed */
GLOBAL(copy_from_gs)
	pushw	%ds
	pushw	%gs
	popw	%ds
	calll	memcpy
	popw	%ds
	retl
ENDPROC(copy_from_gs)

GLOBAL(copy_to_gs)
	pushw	%es
	pushw	%gs
	popw	%es
	calll	memcpy
	popw	%es
	retl
ENDPROC(copy_to_gs)
#endif
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