关于两道汇编语言程序设计的题

1.显示字符串
data segment
mess db 'Hello!','$'
data ends
code segment
assume cs:code,ds:data
start:
mov ax,data
mov ds,ax
lea dx,mess
mov ah,9
int 21h
mov ah,1
int 21h
mov ah,4ch
int 21h
code ends
end start

2.接收字符串输入
data segment
buff db 80,?,80 dup(?)
data ends
code segment
assume cs:code,ds:data
start:
mov ax,data
mov ds,ax
lea dx,buff
mov ah,0ah
int 21h
mov ah,1
int 21h
mov ah,4ch
int 21h
code ends
end start