KeyLeft   equ P1.0
       KeyRight  equ P1.1
       LedLeft   equ P1.2
       LedRight  equ P1.3
       
       SETB   KeyLeft
       SETB   KeyRight
Loop: 
       MOV    C,KeyLeft
       MOV    LedLeft,C
       MOV    C,KeyRight
       MOV    Ledright,C
       LJMP   Loop
       
       END