asembly prog is not working

      RAM location 47 to 52 have data 1,2,3,4,5,6
      average to be taken and result in reg r3


      mov r1,#06h     Counter
      mov b,#06h      Divisor
      mov r0,#47h
      mov a,@ro
  L1  add a,@r0
      inc r0
      djnz r1,L1
      div ab
      mov r3,a
Loop is not working