RO等于多少啊，兄弟们

CHABIAO:MOV R0, #02

                MOV   A,            R0

                RL       A

                MOV   DPTR,     #TAB

                MOVC A,           @A+DPTR

                MOV   R0,          A

                RET

      TAB:   DB    0,1,2,3,4,5,6,7,8,9