I'm trying to understand the configuration and device code for
NetBSD under vax.  On my system:

   ibus0 at mainbus0
   uba0 at ibus0: Q22
   uda0 at uba0 csr 172150 vec 774 ipl 15    (csr = hex 0xf468)
   qe0 at uba0 csr 174440 vec 770 ipl 15     (csr = hex 0xf920)

uba_ibus.c sets up the uba0 with address 0x20000000.  As far
as I can tell this should mean that the bus_space_write_*
commands should write to 0x2000f468 + off and
0x2000f920 + off for the uda0 and qe0 devices.  This doesn't
match up with where my devices really are:

    RQ, address=20001468-2000146B
    XQ, address=20001920-2000192F

these addresses are both 0xe000 lower than I would expect them
to be.  What am I missing here?

Tim N.