data segment
mess1 db 'Input number:0-9$'
errmess db 'error!$'
data ends
stack1 segment
dw 20h dup(0)
stack1 ends
code segment
assume cs:code,ss:stack1,ds:data
start: mov ax,stack1
mov ss,ax
mov sp,64
mov ax,data
mov ds,ax
lea dx,mess1
mov ah,09h
int 21h
mov ah,01h
int 21h
mov bl,al
call newline
cmp al,30h
jb errdeal
cmp al,39h
ja errdeal
mov dl,bl
mov ah,02h
int 21h
jmp short ok
errdeal: lea dx,errmess
mov ah,09h
int 21h
ok: mov ax,4c00h
int 21h
newline proc
push dx
push ax
mov dl,0dh
mov ah,02h
int 21h
mov dl,0ah
mov ah,02h
int 21h
pop ax
pop dx
ret
newline endp
code ends
end start
好吧!帮你做一题!