For all of you who asked:
Why is using BCF and BSF on a port a bad idea?

To get the whole story, look at the data book.  (For the PIC16C84, it is in
 section 5.3.1 in my data
book.)

The short of the story is:
This reads the pins, and then writes back to the latch.  This is okay as long as
 you aren't switching
back and forth pins as input and output.
BUT, if you are using the TRIS register to selectively access pins
(For example, an I2C implementation with external pull-ups where to release the
 bus you simply
tri-state the pin.)
and you do a BCF or BSF instruction then the latch associated with an input pin
 gets written the value
that was on that pin.
For example:

MOVLW  0x00            ; move 0 into W
bcf         STATUS, RP0 ; set to page 0
movwf     PORTA ; move bits to portA
bsf        STATUS, RP0  ; set to page 1
movlw   0x01               ; set A0 as input, rest as outputs
movwf   TRISA
bsf      PORTA, 2        ; This sets pin 2 of portA as 0, and puts the value at
 A0 in the latch
associated with A0.
bcf     TRISA, 0          ; This sets pin 0 of portA as an output and garbage is
 sent out rather than
the 0 that we would
                        ; think

So it is okay to use BCF and BSF if you aren't pulling this kind of trick but be
 careful because it can
bite you!

I hope this helps!

Alan G. Smith
+---------------------------------------------------------
| Alan G. Smith
| ags@poboxes.com
| http://www.innovatus.com/ags