Relating rtems_symbolic_irq_name to vector number

[gregory.menke at gsfc.nasa.gov]

I'm working on getting multiple DEC21140 units to work, so far I'm
making progress- a single board arrangement still works... ;) But I'm
not quite sure how to relate an irqname to the vector that comes in on
the interrupt.  From looking at the bsp's irq management defines it
seems like theres probably a way to work from one to the other, but
due to me not having lots of experience with the ppc, I'm not sure
where to look.  Any hints are appreciated.

Thanks,

Gregm