键盘上接受三个数，选出大于平均数的数据显示出来

INPUT MACRO NO
      PUSH AX
      MOV AH,1
      INT 21H
      MOV NO,AL
      POP AX
    ENDM
DATA SEGMENT
DA1 DB 0
DA2 DB 0
DA3 DB 0
SUM DB 0
  DATA ENDS
STACKS SEGMENT
  STACKS ENDS
CODE SEGMENT
     ASSUME CS:CODE,DS:DATA,SS:STACKS
START: MOV AX,DATA
       MOV DS,AX
       INPUT DA1
       INPUT DA2
       INPUT DA3
       XOR AX,AX
       MOV AL,DA1
       ADD AL,DA2
       ADD AL,DA3
       MOV SUM,AL
       MOV CX,3
       XOR BX,BX
LOP:   MOV AL,DA1[BX]