> From: briggs@puma.macbsd.com
> Date: Fri, 15 Nov 1996 09:47:25 -0500 (EST)

> [ MACHINE_NONCONTIG is an option only for the port maintainer ... ]
> 
> Well, some macs have contiguous memory, others have holes...  The macs
> have been using MACHINE_NONCONTIG for some time (0.9 or 1.0, I think).
> 
> > Maybe this should be stated more prominently in order to at least encourage
> > new porters to code for the MACHINE_NONCONTIG case instead of the old one.
> 
> If we want to do that, it would make sense to reverse the define to
> be MACHINE_CONTIG and define that on the ports where it isn't used.
> It does make some sense to move all ports to the MACHINE_NONCONTIG
> interface since it would mean one less conditional in the VM system
> and the MACHINE_CONTIG can be represented as a MACHINE_NONCONTIG
> configuration with one bank.
> 
> -allen

Yes, replacing this "option" with one of the opposite sense
would help discourage proliferation of the old pmap interface
by making it a little more difficult.  (The port master would
have to consciously add MACHINE_CONTIG 8^)  Maybe the opposite
sense name could be better -- how about PMAP_MEM_CONTIG instead?

So, I propose that we:

(1) Add the PMAP_MEM_CONTIG definition to all ports that do not
    presently use the MACHINE_NONCONTIG option.

(2) Change the VM code conditionals from
	#ifndef MACHINE_NONCONTIG
to
	#ifdef PMAP_MEM_CONTIG	/* old, depreciated way */

(3) Remove the MACHINE_NONCONTIG definition from the
    ports that use the preferred interface.

The intention would be to make it more convenient to use the
preferred interface than to use the depreciated interface.

Gordon