[ECOS] MPC823 interrupt problem?

Linus Nielsen Feltzing linus@haxx.se
Tue Apr 3 14:53:00 GMT 2001


> CYGARC_PPC_EXCEPTION_DECREMENT is a preprocessor symbol which is used
> to adjuste the stack on exceptions. It should never form part of an
> address and I'm surprised that the debugger knows about it at all.

Are you sure? Isn't this the decrementer exception?
This is a common thing when starting up an MPC8xx processor. The decrementer
will start decrementing as soon as the clocks are set up, and since it is
initiated to 0 at reset, it will trigger a decrementer exception as soon as
the interrupt disable bit is cleared in MSR.

I guess that is common knowledge, so I'd rather find out why there isn't
any code in the exception vector area to handle this exception. Maybe
the interrupt prefix bit is modified in MSR by mistake? How is your MPC
configured at reset (I mean the reset configuration on the data bus)?

/Linus




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