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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <grub/symbol.h>
#include <grub/machine/memory.h>
#include <grub/machine/boot.h>
#include <grub/machine/kernel.h>
.text
.code16
.globl _start
_start:
/* Disable interrupts. */
cli
jmp 1f
.org GRUB_BOOT_I386_QEMU_CORE_ENTRY_ADDR
VARIABLE(grub_core_entry_addr)
.long 0
1:
/* Set up %ds, %ss, and %es. */
xorw %ax, %ax
movw %ax, %ds
movw %ax, %ss
movw %ax, %es
/* Set up the real mode stack. */
movl $GRUB_MEMORY_MACHINE_REAL_STACK, %esp
/* Transition to protected mode. We use pushl to force generation
of a flat return address. */
pushl $1f
jmp real_to_prot
.code32
1:
/* Ensure A20 is enabled. We're in qemu, so control port A works
and there is no need to wait since there is no real logic, it's
all emulated. */
inb $0x92
andb $(~0x03), %al
orb $0x02, %al
outb $0x92
movl EXT_C(grub_core_entry_addr), %edx
jmp *%edx
#include "../../../kern/i386/realmode.S"
/* Intel, in its infinite wisdom, decided to put the i8086 entry point
*right here* and this is why we need this kludge. */
.org GRUB_BOOT_MACHINE_SIZE - 16
.code16
jmp _start
.org GRUB_BOOT_MACHINE_SIZE
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