brucec dc1c4b9270 Disallow passing in a count of zero bytes to the bus_space(9) functions.
Passing a count of zero on i386 and amd64 for [I386|AMD64]_BUS_SPACE_MEM
causes a crash/hang since the 'loop' instruction decrements the counter
before checking if it's zero.

PR:	kern/80980
Discussed with:	jhb
2010-12-02 22:19:30 +00:00
..
2010-11-12 20:55:14 +00:00