Hi Andy,

And many thanks for your help. If I tried to invoke a macro on a PIC from
say ram_bank0  to a place in ram_bank1 memory, ( ram_bank0 and ram_bank1
being memory pages) would the macro work?? Or would I have to switch memory
pages first?
I may very well be using the wrong terminology and am new to ram/ memory
paging systems like on the 16c505 or 16c63.

                                                        Regards John

                -----Original Message-----
                From:   Andrew Warren [mailto:fastfwd@IX.NETCOM.COM]
                Sent:   Wednesday, 29 March 2000 3:31
                To:     PICLIST@MITVMA.MIT.EDU
                Subject:        Re: MACROS

                John Orhan <PICLIST@MITVMA.MIT.EDU> wrote:

                > How many times can a macro be called.

                    As many times as you like.

                > Can a macro be called from inside another macro?

                    Yes.

                > What is the difference between a macro and a subroutine?

                    A subroutine exists at just one place in your PIC's
memory; each
                    time you want to use it, you CALL the subroutine from
somewhere
                    else in your program.

                    When you define a macro, NOTHING gets stored in your
PIC's
                    memory.  When you USE the macro, though, a full copy of
it is
                    inserted in your program at the point where you used it.

                    An analogy might help... If you're composing a document
with
                    text and pictures, you can refer to the pictures two
ways:

                    The first way is to have just one copy of the picture,
with "See
                    Figure 1" in your text wherever you want the reader to
look at
                    the picture.  That's a subroutine.

                    The other way is to paste a copy of the picture at each
point in
                    the document where you want the reader to see it.
That's a
                    macro.

                    Make sense?

                > If I happen to call a macro from outside the page limits,
what will
                > happen?

                    I'm not sure what you're asking.  You don't "call"
macros; when
                    you use them, you're just asking the assembler to insert
the
                    body of your macro there in your program... So they
don't behave
                    any differently than if you simply cut-and-pasted code
into your
                    program at that point.

                    -Andy


                === Andrew Warren - fastfwd@ix.netcom.com
                === Fast Forward Engineering - San Diego, California
                === http://www.geocities.com/SiliconValley/2499