;从内存1000H(偏移量)开始,建立19个自然递增有自然递减
;(0-->9-->0)的数据.
data segment
org 1000h
buf db 19 dup(?)
data ends
code segment
assume cs:code,ds:data
start:mov ax,data
      mov ds,ax
      mov cl,13h
      lea si,buf
      mov bx,0
p1:   cmp cl,09h
      jng t1
      mov [si],bx
      inc si
      inc bx
      jmp t2
t1:   cmp cl,09h
      jnz t4
      dec bx
t4:   dec bx
      mov [si],bx
      inc si
t2:   loop p1 
      mov ah,4ch
      int 21h
code ends
     end start