Mike Riendeau <PICLIST@MITVMA.MIT.EDU> wrote:

>First, it's unnecessary; the "empty" code-space is ALREADY filled
>with instructions that won't affect program flow.

Yes, but your program has to wait for the time it takes to
execute the number of (ADDLW ?) instructions, or the WDT timeout
if it is still responding, before the wrap-around.  My
application involves the control of a high power system and
needs to respond immediately to a 'glitch' in the program
counter.  We have brown-out and reset circuitry on-board, as
well as implementation of the WDT, but.... you never know.

>Second, what will those "reset vectors" look like?  Just a bunch of
>GOTOs?

Yes, that's exactly what they are.

> How's that going to work on a
> processor whose code-space is paged?

Yes, you have a point, but it's a red-herring in the scope of
an already out-of control situtation. That is, your wrap-around will
only produce the same page result. If you have the macro loop detect
the first address in an empty page and put in a bit of code
to set the PCLATH register with the appropriate bits; The
GOTO which immediately follows would then vector off to the
appropriate reset address. Not perfect, but it gives you a
better statistical advantage of quickly regaining some
control over the application.

                                Regards,
                                   Mike