自制操作系统5

让我们直接使用硬盘 ;主引导程序;--------------------------------------------------------------------%include 'boot.

让我们直接使用硬盘

;主引导程序;--------------------------------------------------------------------%include 'boot.inc'SECTION MBR vstart=0x7c00	mov ax,cs	mov ds,ax	mov	es,ax	mov ss,ax	mov fs,ax	mov sp,0x7c00	mov ax,0xb800	mov gs,ax;--------------------------------------------------------------------	mov ax,0600h	mov bx,0700h	mov cx,0	mov dx,184fh;--------------------------------------------------------------------	int 10h;--------------------------------------------------------------------	mov byte [gs:0x00],'1'	mov byte [gs:0x01],0xA4	mov byte [gs:0x02],' '	mov byte [gs:0x03],0xA4	mov byte [gs:0x04],'M'	mov byte [gs:0x05],0xA4	mov byte [gs:0x06],'B'	mov byte [gs:0x07],0xA4	mov byte [gs:0x08],'R'	mov byte [gs:0x09],0xA4;--------------------------------------------------------------------	mov eax,LOADER_START_SECTOR	mov bx,LOADER_BASE_ADDR	mov cx,1	call rd_disk_m_16	jmp LOADER_BASE_ADDR	rd_disk_m_16:	mov esi,eax	mov di,cx	mov  dx,0x1f2	mov al,cl	out dx,al	mov eax,esi	mov dx,0x1f3	out dx,al	mov cl,8	shr eax,cl	mov dx,0x1f4	out dx,al	shr eax,cl	mov dx,0x1f5	out dx,al	shr eax,cl	and al,0x0f	or al,0xe0	mov dx,0x1f6	out dx,al	mov dx,0x1f7	mov al,0x20	out dx,al	.not_ready:	nop	in al,dx	and al,0x88	cmp al,0x08	jnz .not_ready	mov ax,di	mov dx,256	mul dx	mov cx,ax	mov dx,0x1f0	.go_on_read:	in ax,dx	mov [bx],ax	add bx,2	loop .go_on_read	ret	times 510-($-$$) db 0	db 0x55,0xaa

命名为mbr_4.S

然后boot.inc为

;------------------loader and kernel--------------LOADER_BASE_ADDR equ 0x900LOADER_START_SECTOR equ 0x2

文件位置如下

[root@makeOS software]# lsbochs  include  mbr_3.S  mbr_4.S  mbr.bin  mbr.S[root@makeOS software]# nasm -I include/ -o mbr.bin mbr_4.S[root@makeOS software]# dd if=./mbr.bin of=bochs/hd60M.img bs=512 count=1 conv=notrunc1+0 records in1+0 records out512 bytes (512 B) copied, 0.0450586 s, 11.4 kB/s

实现内核加载器

%include 'boot.inc'section loader vstart=LOADER_BASE_ADDRmov byte [gs:0x00],'2'mov byte [gs:0x01],0xA4mov byte [gs:0x02],' 'mov byte [gs:0x03],0xA4mov byte [gs:0x04],'L'mov byte [gs:0x05],0xA4mov byte [gs:0x06],'O'mov byte [gs:0x07],0xA4mov byte [gs:0x08],'A'mov byte [gs:0x09],0xA4mov byte [gs:0x0a],'D'mov byte [gs:0x0b],0xA4mov byte [gs:0x0c],'E'mov byte [gs:0x0d],0xA4mov byte [gs:0x0e],'R'mov byte [gs:0x0f],0xA4jmp $

[root@makeOS software]# nasm -I include/ -o loader.bin loader.S[root@makeOS software]# dd if=./loader.bin of=bochs/hd60M.img bs=512 count=1 seek=2 conv=notrunc0+1 records in0+1 records out99 bytes (99 B) copied, 0.000174176 s, 568 kB/s

我们启动虚拟机之后，屏幕上就可以显示” 2 loader “了。