check:
one:
     cjne A,#'A',two
     cpl P1.0
     CLR RI
     SJMP HERE       ;should be a REt here
two:
     cjne A,#'B',three
     cpl P1.1
     CLR RI
     SJMP HERE
three:
     cjne A,#'C',four
     cpl P1.2
     CLR RI
     SJMP HERE
four:
     cjne A,#'D',one  ; one!!!! why 
     cpl P1.3
     CLR RI
     SJMP HERE