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RE: eCos Code at address 0x000? (MPC8270)
- From: "Tim Sohacki" <tsohacki at telesyn dot com>
- To: "'eCos Discussion'" <ecos-discuss at ecos dot sourceware dot org>
- Date: Tue, 18 May 2004 14:47:36 -0400
- Subject: RE: [ECOS] eCos Code at address 0x000? (MPC8270)
Gary Thomas wrote:
>
> On Tue, 2004-05-18 at 11:44, Tim Sohacki wrote:
> > Hello,
> >
> > On the MPC8270, it appears that eCos has some code running at (or
> > near) address 0. I suspect this is eCos specific because the first
PPC
> > interrupt vector stub is at 0x100.
> >
> > What is this code? It appears to be executed at runtime, because if
> > it is trampled, the target will crash. Is it a NULL pointer write
> > detector?
>
> It's just a place holder - in this case, your code will just hang
there
> if you did a jump (or function call) to 0x0.
>
> What do you mean "trampled" and how does the problem show up? That
code
> should never be executed - if it does, your program would just stop.
Interesting. Does that suggest that someone may be calling
a NULL function pointer? Where is the code for this stub?
We've seen some crashes at address 0x4. Dumping that area,
it appeared that the values around 0 had been written to
(trampled), because they no longer matched the power up
values.
Later, I manually "trampled" the area around 0 with a debug
command, and the target crashed shortly afterwards.
Cheers,
Tim.
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