I meant:
toggle GP4 and GP5 to drive the pi‘zo and keep GP0-GP2 unchanged.
So I will try your second solution.

But, being a beginner,

What is meant with:
MASK    equ     GP4 | GP5

> -----Oorspronkelijk bericht-----
> Van: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]Namens Scott Dattalo
> Verzonden: zondag 12 september 1999 17:08
> Aan: PICLIST@MITVMA.MIT.EDU
> Onderwerp: Re: Driving a pi‘zo sounder
>
>
> On Sun, 12 Sep 1999, leo van Loon wrote:
>
> > I want to drive a pi‘zo sounder on pin GP4 and GP5 in
> counter phase with
> > leds driven on GP0 to GP2
> > How can I toggle these two pins with minimum code?
>
> GPn == 1<<n
>
> MASK  equ     GP0 | GP2 | GP4 | GP5
>
>     movlw   GP0 | GP4
>     movwf   GPIO
>
> loop
>     movlw   MASK
>     xorwf   GPIO,f
>     goto    loop
>
> This code toggles the LEDs and the piezo. But I'm not sure if
> that's what
> you're asking.
>
> MASK  equ     GP4 | GP5
>
>     movlw   GP4
>     movwf   GPIO
>
> loop
>     movlw   MASK
>     xorwf   GPIO,f
>     goto    loop
>
> This code toggles the piezo without affecting the LEDs.
>
> Scott
>