Exception routines are not called

Hi!

I’m using gdbtk for debugging an application running NET+OS 6 on the 7520 board. To test the exception routines I try to produce different
kinds of errors by read/write on faulty (non existing) memory. I set breakpoints on all handlers:
Undefined_Handler
SWI_Handler
Prefetch_Handler
Abort_Handler
Address_Error_Handler
FIQ_Handler
Reset_Handler_ROM
crash

Nothing happens, the appplication just seems to hang. If I explicit call the exception routine (from my application) my debugger breaks
and all seems fine. Is there something I have to enable to get exceptions?

Thanks!