assume cs:code
code segment
start:mov ax,cs
mov ds,ax
mov si,offset xunhuan
mov ax,0
mov es,ax
mov di,200h
mov word ptr es:[7ch*4],200h
mov word ptr es:[7ch*4+2],0
mov ax,4c00h
int 21h
xunhuan:push bp
mov bp,sp
dec cx
jcxz ok
add [bp+2],bx
ok:pop bp
iret
code ends
end start