传送,该如何解决

传送
我用的编译器是masm611，为什么我用指令mov ax,0b800h的时候编译出错。报in instruction错
请问如何传送字母带头的地址
附代码：

assume cs:code
code segment
start: mov ax,cs
  mov ds,ax
  mov si,offset do0
  mov ax,0
  mov es,ax
  mov di,200h
  mov cx,offset do0end-offset do0
  cld
  rep movsb
  mov ax,0
  mov es,ax
  mov word ptr es:[0*4],200h
  mov word ptr es:[0*4+2],0
  mov ax,4c00h
  int 21h
do0: jmp short do0start
  db "overflow!"
do0start:mov ax,cs
  mov ds,ax
  mov si,202h
  mov ax,0b800h
  mov es:ax
  mov di,12*160+36*2
  mov cx,9
s: mov al,[si]
  mov es:[di],al
  inc si
  add di,2
  loop s
  mov ax,4c00h
  int 21h
do0end:nop
code ends
end start

------解决方案--------------------

................
...............

do0start:mov ax,cs 
mov ds,ax 
mov si,202h 
mov ax,0b800h 
mov es,ax ----------改为逗号
mov di,12*160+36*2 
mov cx,9 
s: mov al,[si] 
mov es:[di],al 
inc si 
add di,2 
loop s 
mov ax,4c00h 
int 21h 
do0end:nop 
code ends 
end start