;输入小写字母，显示相应的大写母
prognam segment
main proc far
    assume cs:prognam
start:
    mov ah,01h
    int 21h
    cmp al,61h
    jc exit
    cmp al,7ah
    jg exit
    sub al,20h
    mov dl,al
    mov ah,02h
    int 21h
exit:
    ret
main endp
prognam ends
end start