74 lines
1.9 KiB
ArmAsm
74 lines
1.9 KiB
ArmAsm
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <grub/symbol.h>
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#include <grub/machine/memory.h>
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#include <grub/machine/boot.h>
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#include <grub/machine/kernel.h>
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.text
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.code16
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.globl _start
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_start:
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/* Disable interrupts. */
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cli
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jmp 1f
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. = _start + GRUB_BOOT_I386_QEMU_CORE_ENTRY_ADDR
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VARIABLE(grub_core_entry_addr)
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.long 0
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1:
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/* Set up %ds, %ss, and %es. */
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xorw %ax, %ax
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movw %ax, %ds
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movw %ax, %ss
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movw %ax, %es
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/* Set up the real mode stack. */
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movl $GRUB_MEMORY_MACHINE_REAL_STACK, %esp
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/* Transition to protected mode. We use pushl to force generation
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of a flat return address. */
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pushl $1f
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jmpl real_to_prot
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.code32
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/* Ensure A20 is enabled. We're in qemu, so control port A works
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and there is no need to wait since there is no real logic, it's
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all emulated. */
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inb $0x92
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andb $(~0x03), %al
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orb $0x02, %al
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outb $0x92
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1:
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movl EXT_C(grub_core_entry_addr), %edx
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jmp *%edx
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#include "../../../kern/i386/realmode.S"
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/* Intel, in its infinite wisdom, decided to put the i8086 entry point
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*right here* and this is why we need this kludge. */
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. = GRUB_BOOT_MACHINE_SIZE - 16
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.code16
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jmp _start
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. = GRUB_BOOT_MACHINE_SIZE
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