data segment
x db 1
y db 2
z db ?
data ends
code segment
  assume cs:code,ds:data
  main proc far
start: 
    mov ax,data
    mov ds,ax
    mov ah,x
	add ah,y//加法运算，把结果存到ah里
    mov dl,ah
	add dl,30h
	mov ah,02h//二号指令调用，输出3
    int 21h
	mov ah,4ch
	int 21h
	main endp
code ends
end start