汇编调用函数问题

;输入一个数N，要求响铃N次，调用延迟函数
data segment
data ends
stack segment stack
  buff db 100 dup(?)
stack ends
code segment
  assume cs:code,ds:data
;---------------------------------
main proc far
start:
  push ds
  sub ax,ax
  push ax
  mov ax,data
  mov ds,ax
  mov ah,01h
  int 21h
  mov cl,al
rotate:
  mov dl,07
  mov ah,02h
  int 21h
  call delay
  loop rotate
  ret
delay:
  mov cx,0100h
d:  
  dec cx
  cmp cx,0h
  jae d
ret
main endp
;-----------------------------------
code ends
end start
 

怎么调用？代码怎样改