> This was neither the doc's fault nor, in most respects, the hardware's.
> It seems the gcc version I was using for this takes
> 
> 	struct foo { ... } __attribute__((__packed__));
> 
> to imply also __aligned__(1) - or at least it does four one-byte
> loads/stores rather one four-byte load/store to access a four-byte
> field.  (I finally got desperate enough to look at the assembly code.)
> 

A good reason to use bus_space_*() functions to access the device registers.
Though in this case just dropping __packed__ should be ok, since all fields
are 32 bit ints anyway.

-pk