The best way I know to swap W and a file takes 3 instructions, but no
termporary locations:

    xorwf    file,F
    xorwf    file,W
    xorwf    file,F

(work it out, it does swap em!)

I don't think you'll find much improvement possible on your MOVF/MOVWF
buffer shift routine (if speed is the issue).

Bob Ammerman
RAm Systems





----- Original Message -----
From: "Edson Brusque" <ebrusque@TERRA.COM.BR>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, February 13, 2002 4:51 PM
Subject: [PIC]: SWAPWF ???


> Hello,
>
>     I think I'm doing an stupid question, but there's a way to swap the
> contents of W and a file on a single instruction?
>
>     I want to shift the values inside a buffer and I know I can do:
>
>         MOVF   buf1,W
>         MOVWF  buf0    // buf0 = buf1
>         MOVF   buf2,W
>         MOVWF  buf1    // buf1 = buf2
>         MOVF   buf3,W
>         MOVWF  buf2    // buf2 = buf3
>         MOVF   buf4,W
>         MOVWF  buf3    // buf3 = buf4
>         CLRF   buf4    // buf4 = 0
>
>     But I was thinking if it's possible to make such a thing like:
>
>         MOVLW 0;
>         swapwf buf4; // w=buf4 buf4=0
>         swapwf buf3; // w=buf3 buf3=buf4
>         swapwf buf2; // w=buf2 buf2=buf3
>         swapwf buf1; // w=buf1 buf1=buf2
>         swapwf buf0; // w=buf0 buf0=buf1
>
>     I know that the PIC have no instruction like SWAPWF, but...
>
>     Best regards,
>
>     Brusque
>
> -----------------------------------
> Edson Brusque
> Research and Development
> C.I.Tronics Lighting Designers Ltda
> Blumenau  -  SC  -  Brazil
> www.citronics.com.br
> Say NO to HTML mail
> -----------------------------------
>
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>

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