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/*
* GRUB Utilities -- Utilities for GRUB Legacy, GRUB2 and GRUB for DOS
* Copyright (C) 2007 Bean (bean123@126.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/machine/kernel.h>
.file "g2hdr.S"
.text
.code16
.globl start, _start
start:
_start:
// We are at 0x2000:0
// Move itself to 0x800:0
// Don't modify dx
cld
movw %cs, %ax
movw %ax, %ds
movw $0x800, %ax
movw %ax, %es
xorw %si, %si
movw %si, %di
movw $0x80, %cx
rep
movsl
ljmp $0, $(jump_start-start+0x8000)
jump_start:
// Move data from 0x2040:0 to 0x820:0
movw $0x2040, %ax
movw %ax, %ds
movw $0x820, %ax
movw %ax, %es
xorl %eax, %eax
movb %dh, (GRUB_DECOMPRESSOR_I386_PC_BOOT_DEVICE + 2)
movl GRUB_DECOMPRESSOR_MACHINE_COMPRESSED_SIZE, %eax
addl $GRUB_DECOMPRESSOR_I386_PC_MAX_DECOMPRESSOR_SIZE, %eax
xorl %ecx, %ecx
1:
xorw %si, %si
movw %si, %di
movw $0x8000, %cx
cmpl %ecx, %eax
jae 2f
movw %ax, %cx
2:
pushw %cx
addw $3, %cx
shrw $2, %cx
rep
movsl
popw %cx
movw %ds, %si
addw $0x800, %si
movw %si, %ds
movw %es, %si
addw $0x800, %si
movw %si, %es
subl %ecx, %eax
jnz 1b
ljmp $0, $(0x8000 + 0x200)
. = _start + 0x200 - 2
.word 0xAA55
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