I've just added some code that should detect Pentium chips with the
fdiv bug.  If you have a buggy chip, during autoconfig you should see
something like:

npx0 at isa0 port 0xf0-0xff: using exception 16
WARNING: Pentium FDIV bug detected!

If you have a buggy chip, and don't see this message from the new
probe routine, let me know.