boot.asm

源代码 编译后的二进制文件能直接被裸机加载运行

assume cs:code

code segment

start:

mov ax,07c0h
mov ds,ax
mov es,ax

mov ax,offset bootmessage1
mov bp,ax

mov ah,13h
mov cx,12
mov dh,10h
mov dl,0
mov bh,0
mov bl,0dh
mov al,1
int 10h

mov ax,offset bootmessage2
mov bp,ax

mov ah,13h
mov cx,20
mov dh,11h
mov dl,0
mov bh,0
mov bl,0dh
mov al,1
int 10h

oo:
mov ah,2
int 1ah 

mov al,ch 
cbw 
call change 
mov al,':' 
mov ah,0eh 
int 10h 
mov al,cl 
cbw 
call change 
mov al,':' 
mov ah,0eh 
int 10h 
mov al,dh
cbw 
call change  

mov dh,11h
mov dl,20d
mov ah,2
int 10h

jmp oo

change proc 
push ax 
push cx 
push dx 
mov dx,0 
mov cx,16 
div cx 
add al,30h 
mov ah,0eh 
int 10h 
add dl,30h 
mov al,dl 
mov ah,0eh 
int 10h 
pop dx 
pop cx 
pop ax 
ret 
change endp 

bootmessage1: db "Hello World!"
bootmessage2: db "The current time is:"

code ends

end start