how do i get register state from process before interrupt?

[Jim <jimssubs@telus.net>]

I have a number of processes and drivers on a SB1250 card
and I suspect one of the drivers is misbehaving such that
user processes are not getting a chance to run.  I implemented
a rudimentary watchdog in the timer interrupt which is kicked
by one such user process if things when things are fine.
How would I capture the register state of the process
that was running before the interrupt is run?  I'm on
linux 2.4.18.

Thanks,
Jim