PowerPC interrupt setup

Hi, I am stuck with porting the Fiasco microkernel to PowerPC. I can't find any clear documentation about how to setup a interrupt description table. So, these are my questions: 1. How is an interrupt descriptor formed on PowerPC? How does it look? 2. Where (in memory) do I need to store these descriptors? The IBM PowerPC Programming Manual gives me a good overview but no information on how to implement it. Can someone please point me to some meaningful documentation? Regards, Matthias.