初学者问题

[snowingboy]

data segment
string db "Helloworldasm"
SET equ 3
LEN equ 8
sub db 8 dup(?),0dh,0ah,'$'
data ends



code segment
assume cs:code,ds:data
mov ax,data
mov ds,ax

start:

mov di,offset sub
lea si,offset string
add si,SET
sub si,1
mov cx,LEN
cld
rep movsb


mov ah,09h
mov bx,offset sub
int 21h

mov ah,4ch
int 21h
code ends
end start


..................................................
strsub.asm(5): error A2008: syntax error : db
strsub.asm(17): error A2008: syntax error : sub
strsub.asm(27): error A2008: syntax error : sub

大侠们,帮我看看,小弟真不知道为什么错了.
分析一下,谢谢..

[BAYNPU]

data segment
string db "Helloworldasm"
SET equ 3
LEN equ 8
sub1 db 8 dup(?),0dh,0ah,'$' ;变量名不能采用汇编系统的保留字。
data ends
code segment
assume cs:code,ds:data
mov ax,data
mov ds,ax
start:
mov di,offset sub1
lea si,offset string
add si,SET
sub si,1
mov cx,LEN
cld
rep movsb
mov ah,09h
mov bx,offset sub1
int 21h
mov ah,4ch
int 21h
code ends
end start

[snowingboy]

Thank you ......

^-^