🚀 go-pugleaf

> I've noticed that the high byte of an address (the 68000 only uses the bottom
> 24 bits) is used alot in the Mac for special purposes.

Well, let's hope that no future Mac software ever desires >16MB of address
space (which will probably be true for quite a while) - a certain big blue
computer company started doing this ~20 years ago on a certain line of their
computers; now that they're running out of address space, they had to
introduce a mode bit into their machines, and a whole new version of the
OS to handle it, and the trade tabloids are *still* talking about the
hassles of converting to MVS/XA.

The 68012 and 68020 don't have mode bits, although if the upper 8 bits don't do
anything other than leave the chip on appropriate pins, this can be handled
in off-chip logic (i.e., run those lines to /dev/null).

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy