Does this work if CHOICE1, CHOICE2 and CHOICE3
are GPR's and not litterals ? It's MPASM that
does the "^" thing, isn't it ?

Of course, "fixed" command tables may be more common
then tables with dynamicly changing choice's.

Jan-Erik.

-----Original Message-----
From: Andrew Warren [mailto:aiw@CYPRESS.COM]
Sent: den 26 juni 2003 03:00
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: Comparing between 2 bytes


QAC <PICLIST@mitvma.mit.edu> wrote:

> On the 18-series there is a "compare" instruction that does not
> change anything
> ....
> Nice for "command-tables" since you don't have to reload WREG
> between the compares.

Jan-Erik:

You don't have to reload WREG, even without a non-destructive
"compare" instruction:

    MOVF    COMMAND,W
    XORLW   CHOICE1
    BZ      DOCOMMAND1

    XORLW   CHOICE2^CHOICE1
    BZ      DOCOMMAND2

    XORLW   CHOICE3^CHOICE2
    BZ      DOCOMMAND3

    etc...

-Andy

P.S.  Before anyone asks... The "BZ" pseudo-op is clearly documented
in the MPASM User's Guide somewhere in or near Appendix B, and in the
MPASM.HLP file under Instruction Sets:12-Bit Core Instruction Set:12-
Bit/14-Bit Core Special Instruction Mnemonics.

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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