Glen wrote:

> I have a delay & want to toggle 2 o/ps together.

> =======vars=====
> on      equ     b'00110000'    ;set portb 4 & 5 to 1
> off     equ     b'00000000'    ;set portb 4 & 5 to 0
> toghv   equ     0x04
> toglv   equ     0x02
> ====prog====
  tog     MOVLW   on
          MOVWF   PORTB
          MOVLW   toghv
>         MOVWF   togh
> delh    DECFSZ  togh
>         GOTO    delh
          MOVLW   off
          MOVWF   PORTB
          MOVLW   toglv
>         MOVWF   togl
> dell    DECFSZ  togl
>         GOTO    dell
>         BTFSC   PORTB,3     ;skip next if 0 , checks for 0 ac cycle
>         GOTO    tog
>         RETURN

  Your "togh" and "togl" register locations could be combined to one
called "count" or similar.

  Shadow registers are only required where you don't know what the
values of all output pins need to be at each stage, so the ones you
don't know are stored in the shadow.  Where you know the desired states
of *all* the outputs at each step, you just set the port to that value
as above.

  If you have to do that often, you set a macro such as:

MOVLF   MACRO   lit,file
        MOVLW   lit
        MOVWF   file
        ENDM

  .. which now allows you to say:  MOVLF on,PORTB
or even more specific:

SETPTB  MACRO   lit
        MOVLW   lit
        MOVWF   PORTB
        ENDM

  .. so you can say:  SETPTB on

  Standard warning:  You often can't use a conditional skip in front of
a macro.
--
  Cheers,
        Paul B.