mirror of
https://github.com/grub4dos/ntloader.git
synced 2025-05-08 19:51:14 +08:00
135 lines
3.1 KiB
ArmAsm
135 lines
3.1 KiB
ArmAsm
/*
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* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* 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 this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* @file
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*
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* Startup code
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*
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*/
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#include "ntloader.h"
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#define WARM_REBOOT_FLAG 0x0472
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#define WARM_REBOOT_MAGIC 0x1234
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#define KC_CMD 0x64
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#define KC_CMD_RESET 0xfe
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.section ".note.GNU-stack", "", @progbits
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#if defined(__i386__) || defined(__x86_64__)
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.code32
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.arch i386
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/* Startup code */
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.section ".text", "ax", @progbits
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.globl startup
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startup:
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/* Reload GDT, IDT, and all segment registers, and set up stack */
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lgdt gdtr
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lidt idtr
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ljmp $FLAT_CS, $1f
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1: movw $FLAT_DS, %ax
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movw %ax, %ds
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movw %ax, %es
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movw %ax, %fs
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movw %ax, %gs
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movw %ax, %ss
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movl $_estack, %esp
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/* Jump to C code */
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call main
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/* Should never return */
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jmp reboot
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.size startup, . - startup
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/* Reboot system */
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.section ".text", "ax", @progbits
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.globl reboot
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reboot:
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/* Attempt a warm reboot via the keyboard controller */
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movw $WARM_REBOOT_MAGIC, WARM_REBOOT_FLAG
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movb $KC_CMD_RESET, %al
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outb %al, $KC_CMD
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/* If that failed, generate a CPU triple fault */
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int $0xff
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/* If even that failed, hang the system */
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1: hlt
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jmp 1b
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.size reboot, . - reboot
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/* Global descriptor table */
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.section ".rodata16", "aw", @progbits
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.balign 8
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gdt:
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.globl gdtr
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gdtr:
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.word gdt_limit
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.long gdt
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/* 64 bit long mode code segment */
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.org ( gdt + LM_CS )
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.word 0, 0
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.byte 0, 0x9b, 0x20, 0
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/* 32 bit protected mode flat code segment */
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.org ( gdt + FLAT_CS )
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.word 0xffff, 0
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.byte 0, 0x9f, 0xcf, 0
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/* 32 bit protected mode flat data segment */
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.org ( gdt + FLAT_DS )
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.word 0xffff, 0
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.byte 0, 0x93, 0xcf, 0
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/* 16 bit flat real mode code segment with base BASE_ADDRESS */
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.org ( gdt + REAL_CS )
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.word 0xffff, ( BASE_ADDRESS & 0xffff )
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.byte ( BASE_ADDRESS >> 16 ), 0x9b, 0x8f, 0
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/* 16 bit flat real mode data segment with base BASE_ADDRESS */
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.org ( gdt + REAL_DS )
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.word 0xffff, ( BASE_ADDRESS & 0xffff )
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.byte ( BASE_ADDRESS >> 16 ), 0x93, 0x8f, 0
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.size gdt, . - gdt
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.equ gdt_limit, . - gdt - 1
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/* Interrupt descriptor table */
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.section ".bss16", "aw", @nobits
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.balign 8
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idt:
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.space ( 256 * 8 ) /* 256 8-byte entries */
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.size idt, . - idt
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.equ idt_limit, . - idt - 1
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/* Interrupt descriptor table register */
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.section ".rodata16", "aw", @progbits
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.globl idtr
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idtr:
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.word idt_limit
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.long idt
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.size idtr, . - idtr
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/* Stack */
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.section ".stack", "aw", @nobits
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.balign 8
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_stack:
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.space ( 64 * 1024 )
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.size _stack, . - _stack
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_estack:
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#endif /* defined(__i386__) || defined(__x86_64__) */
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