> Using indirect addressing allows one routine to be called with pointers
> to  the data to be moved, so a small amount of code space can serve many
> purposes.  Here's a general purpose move routine which isn't optimized at
> all but it should work.

My personal "taste" is to have one version coded for either each source or
each destination, which takes a pointer to the "other" operand as input.
Thus, for example, if variables are four bytes...

stow_var1:
        movwf   FSR
        movf    var1,w
        movwf   INDF
        incf    FSR
        movf    var1+w
        movwf   INDF
        incf    FSR
        movf    var1+w
        movwf   INDF
        incf    FSR
        movf    var1+w
        movwf   INDF
        retlw   0

etc. for each variable to be moved.  Then, to do

  var3 := var1

you would simply code:

        movlw   var3
        call    stow_var1

To minimize the code required by the assorted load and stow functions, you
may give some variables both load-and-store capabilities and others neither.
In the event that you need, e.g.,

  var3 := var2

and you don't have a load function for var3 or a stow for var2, and time
is not critical (but space is) and var1 is available, you could code:

        movlw   var2
        call    load_var1
        movlw   var3
        call    load_var1

This would take more than twice as long to execute as doing the move directly,
but only require half as much code space.