and bcopy and bzero were being used. The latter use longs to copy/zero,
and some ethernet cards can't handle longs. I've added bbcopy and bbzero
as a temporary hack, but these should later be added to locore and maybe
changed to use shorts. Still doesn't work: I can now get an interrupt on
the first transmit, but further transmits don't generate more interrupts.
cd701f50a3