Ticket #4203 clarification

zack leung zakthertemsdev at gmail.com
Sat Sep 4 00:27:48 UTC 2021


Say i find an exception (ex format string printing a decimal.) How do I
test that my improvement works?

Thanks
Zack

On Fri, 3 Sept 2021 at 01:36, Joel Sherrill <joel at rtems.org> wrote:

> On Thu, Sep 2, 2021 at 8:01 PM zack leung <zakthertemsdev at gmail.com>
> wrote:
> >
> > Hello!
> >
> > I'd like to begin working on 4203. It involves improving the exception
> output  I'd like to know how I spot exceptions that could be reported
> better by the system?   How do I also know how do I test it and what BSPs i
> can test with only my computer Also joel told me The list of exception
> number/names is in the manual for the architecture. For an i386 or later,
> that should be in many places. Where do i find the documentation of the
> bsps?
> >
>
> Bringing this over from chat.
>
> The methods are architecture specific and may be in score/cpu or
> bsps/shared or a specific BSP (hope now there). For an example,
> score/cpu/i386/cpu.c has an exception printer. It seems to be the one
> cited as an example that could be improved. The thread id is printed
> in decimal, not hex. The exception type is only printed as a number.
> This could be turned into a number and exception name. The list of
> exception number/names is in the manual for the architecture. For an
> i386 or later, that should be in many places. There is only so much
> information in the exception frame passed in, so just make it more
> useful. If you look on other architectures for similar exception
> printers, you may find some print RTEMS state. Perhaps that's common
> info that could be printed by a shared subroutine.
>
> For a manual, this is the grandparent for i386 info:
>
> https://css.csail.mit.edu/6.858/2014/readings/i386.pdf
>
> And yes, that is from 1986 and I think I have a paper copy that old.
> But all x86 info should be essentially the same as what's presented in
> there. There may be additions but that's the original root.
>
> I wouldn't look actively at other architecture exception handlers. You
> could easily get lost in the details of each architecture and
> confused. Focus on the i386 first and how it could be better. For
> example, taking the exception number of printing a string name so you
> don't have to look it up. You find the list in the manual.
>
> FWIW I think the PowerPC prints numbers also.
>
> The name of the handler may be architecture specific. Hopefully
> someone can point to some for other architectures. But a good solution
> on x86 would be a good start.
>
> --joel
>
> --joel
> > Thanks
> >
> > Zack
> > _______________________________________________
> > devel mailing list
> > devel at rtems.org
> > http://lists.rtems.org/mailman/listinfo/devel
>
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