uba_hd->lastiv

[ron%brl-vgr at sri-unix.UUCP]

From:      Ron Natalie <ron at brl-vgr>

uba_hd->lastiv is the last allocated unibus interrupt vector.
It is used for "smart" peripherals that you tell them where to
interrupt to under program control.  The way to use it is to
decrement it by 4 (2 bytes for the PC, 2 bytes for the PS) and
use the resulting number as the vector for that peripheral.

It is just set in autoconf right before the ubaaccess call to
some reasonable number (0x200 by default).

-Ron