;一个两位十进制数加法程序,从键盘上输入:n1n2+n3n4
;则在CRT上显示: ＝n5n6
data segment
org 1000h
buf db 5 dup(?)
data ends
stack segment stack
db 100 dup(?)
stack ends
code segment
assume cs:code,ds:data,ss:stack
start: mov ax,data      
       mov ds,ax
       mov ax,stack
       mov ss,ax
       lea si,buf
       mov cx,5
p1:    mov ah,1
       int 21h
       mov [si],al
       inc si
       loop p1
       call q1      ;等号
;***************************
       lea si,buf
       mov al,[si]
       cmp al,'0'
       jb x1
       cmp al,'9'
       ja x1
       and al,0fh
       mov cl,4
       shl al,cl
       mov ah,al
       inc si
       mov al,[si]
       cmp al,'0'
       jb x1
       cmp al,'9'
       ja x1
       and al,0fh
       or al,ah
       inc si
       inc si
       mov bl,[si]
       cmp bl,'0'
       jb x1
       cmp bl,'9'
       ja x1
       and bl,0fh
       mov cl,4
       shl bl,cl
       mov bh,bl
       inc si
       mov bl,[si]
       cmp bl,'0'
       jb x1
       cmp bl,'9'
       ja x1
       and bl,0fh
       or bl,bh
       adc al,bl
       daa           ;**
       jnc t1
       push ax
       mov al,'1'
       call z1
       pop ax
t1:    mov ah,al
       mov cl,4
       shr al,cl
       add al,30h
       call z1
       mov al,ah
       and al,0fh
       add al,30h
       call z1
x1:    mov ah,4ch
       int 21h
q1     proc
       push ax
       push bx
       push cx
       push dx
       mov dl,3dh
       mov ah,2
       int 21h
       pop dx
       pop cx
       pop bx
       pop ax
       ret
q1     endp
z1     proc
       push ax
       push bx
       push cx
       push dx
       mov dl,al
       mov ah,2
       int 21h
       pop dx
       pop cx
       pop bx
       pop ax
       ret
z1     endp
code   ends
       end start