[ECOS] Axiom CME-555: RedBoot ROM crashing

[Bob Koninckx]

Eric, sorry that it took me so long to reply. Becoming a father is a
good excuse tough :-)


On Tue, 2004-05-25 at 16:03, Eric Gregory Castle wrote:

> That's what I'd hoped, but using OCD commander and the wiggler seems to
> give rather bogus results.  Stepping through results in rather random
> jumping that quickly ends at unknown opcodes or address 0xFFFFFFFF.
> 
> Is there some sort of settings that need to be enabled to use a background
> debugger?
> 

hmmm... stepping one instruction at a time should work since it does not
require write access to program memory on the powerpc. Are you sure you
initialize th processor as it should _before_ trying to step? You find
info on how to do this on axiom's website. Make sure your debugger works
using some piece of working software.

...

> > Floating point? Redboot does not use floating point instructions. May be
> > usefull for debugging to purposes to turn them on anyway
> 
> Did you mean on, or to turn off floating point?

Turn them on. Even if redboot does not use them, the application you are
debugging might. Turning on floating point support makes sure redboot
saves floating point registers, enabling GDB to display their contents.

> I had all of these set except the last.  This alters the priority of the
> serial module; why?

It is not really necessary I suppose. Just gave you the configuration
that works for me.

> >
> > Try stepping through the code from the reset vector and see how far you
> > get. Make sure the reset vector effectively gets you to the _start
> > routine. From what you describe, I doubt it will be the case.
> 
> No, it doesn't seem to.  Any idea why?
> 

Nope. That's for you to find out :-)




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