In article <9704132317.aa23643@jupiter.cis.udel.edu>,
Chester@CIS.UDEL.EDU writes
>A version of the program that uses a loop without a subroutine call is
>this:
>
>          device      pic16c84
>          org         0
>          movlw       0
>          tris        portb ; all port b pins are output
>          movlw       1
>          movwf       portb
>flop      movlw       0
>          movwf       portb
>          goto        flop

You haven't written anything to INTCON have you?  'cause if you had
interrupts enabled then that would cause your symptoms (you're program
starts at org 00 and goes over the 04h interrupt vector - which is bad
practice anyway, 'cause your class is going to want to use interrupts at
some stage)

hope this is of some use

Jim
--
Jim Main
jim@ewcomm.demon.co.uk
Visit Eastwood Communications at http://www.ewcomm.demon.co.uk
Broadcast Electronics & Custom Design