2013-01-08 21:05:02 +08:00
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/*
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* File : start.S
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* This file is part of RT-Thread RTOS
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* COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rt-thread.org/license/LICENSE
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*
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* Change Logs:
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* Date Author Notes
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* 2006-09-15 QiuYi The first version.
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* 2012-02-15 aozima update.
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*/
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/* the magic number for the multiboot header. */
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#define MULTIBOOT_HEADER_MAGIC 0x1BADB002
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/* the flags for the multiboot header. */
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#define MULTIBOOT_HEADER_FLAGS 0x00000003
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#define CONFIG_STACKSIZE 8192
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/**
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* @addtogroup I386
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*/
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/*@{*/
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.section .init, "ax"
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/* the system entry */
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.globl _start
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_start:
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jmp multiboot_entry
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/* Align 32 bits boundary. */
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.align 4
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/* multiboot header. */
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multiboot_header:
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/* magic */
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.long MULTIBOOT_HEADER_MAGIC
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/* flags */
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.long MULTIBOOT_HEADER_FLAGS
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/* checksum */
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.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
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multiboot_entry:
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movl $(_end + 0x1000),%esp
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/* reset eflags. */
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pushl $0
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popf
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/*rebuild globe describe table*/
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lgdt mygdtdesc
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movl $0x10,%eax
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movw %ax,%ds
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movw %ax,%es
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movw %ax,%ss
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ljmp $0x08, $relocated
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relocated:
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/* push the pointer to the multiboot information structure. */
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pushl %ebx
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/* push the magic value. */
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pushl %eax
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call rtthread_startup
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/* never get here */
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spin:
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hlt
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jmp spin
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.data
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.p2align 2
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mygdt:
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.word 0,0,0,0
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.word 0x07FF /* 8Mb - limit=2047 */
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.word 0x0000
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.word 0x9A00 /* code read/exec */
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.word 0x00C0
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.word 0x07FF /* 8Mb - limit=2047 */
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.word 0x0000
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.word 0x9200 /* data read/write */
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.word 0x00C0
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mygdtdesc:
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.word 0x17
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.long mygdt
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/*@}*/
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