Excerpt from Gwilym Evans:

   Also I just tried to reboot it and got this:

   swapctl: adding /dev/wd0b as swap device at priority 0
   Automatic boot in progress: starting file system checks./dev/rwd0a: 3634
   files, 27625 used, 56859 free (1155 frags, 6963 blocks, 1.4% fragmentation)
   /dev/rwd0a: MARKING FILE SYSTEM CLEAN
   kernel: page fault tap, code=0
   Stopped at if_slowtimo+0x24: movw 0x2e(%ebx),%ax
(end of quote)

This looks like a size inconsistency between registers.  ebx is 4 bytes, ax is
2 bytes.  Source and destination of mov commands must be same size.  Or is my
interpretation of the error message wrong?