Breakpoints Inside Interrupt Handlers - Intel i960 User Manual

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Caveats

Breakpoints Inside Interrupt Handlers

If your application uses interrupts extensively, when debugging interrupt
handlers with gdb960, breakpoints set inside the handlers may not work
and may result in operation faults.
Problem:
When the i960 processor invokes an interrupt handler, it first disables
tracing by saving, then clearing, the state of the trace-enable bit and the
trace-fault-pending flag. On return from the interrupt handler, the
processor restores the process-controls register to its state prior to the
interrupt. This restores the state of the trace-enable bit and the
trace-fault-pending flag; therefore, standard interrupt handlers cannot
contain breakpoints.
Solution:
To set breakpoints inside an interrupt handler, you can modify that
handler, probably in the assembler wrapper, adding code to change the
state of the trace-enable bit.
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