上一篇讲到了将kernel模块加载到了内存的0x10000-0x10000+120KB处，接下来，将会执行setup.s中的代码了。

首先，setup要获取一系列系统硬件信息

mov	ax,#INITSEG	
mov	ds,ax           //设置段地址
mov	ah,#0x03	
xor	bh,bh
int	0x10		//调用0x10中断获取屏幕光标位置
mov	[0],dx		//将屏幕光标保存至0x90000处
//调用0x15中断，获取内存信息保存至0x90002
mov ah,#0x88 
int 0x15mov [2],ax
//调用0x10中断，获取显卡信息保存至0x90004 - 0x90006
mov ah,#0x0f
int 0x10
mov [4],bx 
mov [6],ax
//调用0x10中断，获取VGA/EGA配置保存至0x90008 - 0x900012
mov ah,#0x12
mov bl,#0x10
int 0x10
mov [8],ax
mov [10],bx
mov [12],cx
//获取hd0信息
mov ax,#0x0000
mov ds,ax
lds si,[4*0x41]
mov ax,#INITSEG
mov es,ax
mov di,#0x0080
mov cx,#0x10
rep
movsb
//获取hd1信息
mov ax,#0x0000
mov ds,ax
lds si,[4*0x46]
mov ax,#INITSEG
mov es,ax
mov di,#0x0090
mov cx,#0x10
rep
movsb
//检查是否存在hd1
mov ax,#0x01500
mov dl,#0x81
int 0x13
jc no_disk1
cmp ah,#3
je is_disk1
no_disk1:mov ax,#INITSEG
mov es,ax
mov di,#0x0090
mov cx,#0x10
mov ax,#0x00
rep
stosb
is_disk1:

接下来为了方便进行内核的地址映射，将system模块从0x10000处移动至0x00000处

do_move:
	mov	es,ax		//指定目标段基址
	add	ax,#0x1000
	cmp	ax,#0x9000
	jz	end_move
	mov	ds,ax		//指定源段基址
	sub	di,di
	sub	si,si
	mov 	cx,#0x8000
	rep
	movsw
	jmp	do_move

end_move:
	mov	ax,#SETUPSEG	
	mov	ds,ax
	lidt	idt_48		
	lgdt	gdt_48		

	call	empty_8042
	mov	al,#0xD1		
	out	#0x64,al
	call	empty_8042
	mov	al,#0xDF		
	out	#0x60,al
	call	empty_8042

linux内核设计的艺术--从16位转向32位