RETADR_H         EQU      0Dh
RETADR_L         EQU      0Eh

                 MOV      A,#3*2            ; Each LJMP instruction is 3 bytes long
                 LCALL    SWITCH_THING
                 LJMP     ROUTINE_FOR_0
                 LJMP     ROUTINE_FOR_1
                 LJMP     ROUTINE_FOR_2     ; <- Returns here
                 LJMP     ROUTINE_FOR_3
                 ...
                 LJMP     ROUTINE_FOR_85    ; <- EDIT: Only 85


SWITCH_THING:    POP      RETADR_H          ; Get return address from stack
                 POP      RETADR_L          ; Was pushed HI byte last
                 ADD      A,RETADR_L
                 MOV      RETADR_L,A
                 ADDC     A,RETADR_H
                 MOV      RETADR_H,A
                 PUSH     RETADR_L          ; Put the modified address back to stack
                 PUSH     RETADR_H
                 RET                        ; Do a return to the new modified address