You can do all sorts of TMR0/RTCC stuff.  On one application, I use TMR0 to
synchronize data capture with distortions, and do resync arithmetic under
certain conditions:
        MOVLW   IDEALVALUE              ; theoretical value
        SUBWF   RTCC,W          ; error
        SUBWF   RTCC,F                  ; adjust clock by error
Works fine.
  <edtodd@sni.net>    Ed Todd