汇编学习1

显示字符的方法

1.      利用bios中断

 

DOS显示字符串的功能调用为：
MOV Dx，字符串的偏移地址
MOV AH．9
INT 21H

 

DOS显示字符的功能调用为：
MOV AH．2
MOV DL，字符ASCII码
INT 21H

(1)

dsegsegment

mess db'hello',13,10,'$'

dseg ends

 

csegsegment

assumecs:cseg

movax,dseg

mov ds,ax

leadx,mess

mov ah,9

int 21h

 

mov ah,4ch

int 21h

cseg ends

end

 

这段代码的hello若改成helloworld

就必须改成

dseg segment

mess db 'helloworld',13,10,'$'

dseg ends

stack segment

db 100 dup(0)

stack ends

 

cseg segment

assume cs:cseg,ss:stack

mov ax,dseg

mov ds,ax

lea dx,mess

mov ah,9

int 21h

 

mov ah,4ch

int 21h

cseg ends

end

因为系统默认的堆栈大小不够，简称的堆栈溢出

 

(2)

code segment

assume cs:code

mov cx,26

mov dl,'A'

next:mov ah,02h

int 21h

inc dl

loop next

 

mov ah,4ch

int 21h

code ends

end

 

2.      利用显存[0xb8000—0xbffff]来显示字符

 code segment

assume cs:code

       mov ax,0b800h

       movds,ax

      

       moval,41h

       movah,0

       movds:[0],al

     

       mov ah,4ch

       int21h

code ends

end

这个程序会在debug的上面显示