Over the past few months, I've been using bitfield - a script to decode the fields within a register. It does neat stuff like this:

[jk@pokey ~]$ bitfield IOC_PTE 0xb80000000140031c
decoding as Cell IOMMU Page table entry
0xb80000000140031c [13258597302999712540]
   Page protection: 0x2 [write]
Coherence required: 0x1
  Storage ordering: 0x3 [reads & writes]
               RPN: 0x1400
              IOID: 0x31c

It's handy for those "did I really tell the hardware to do that?" problems.

Download and documentation over here.