There is a generic sun4m architecture specification to which all
sun4m machines conform.  This includes the generic sun4m MP features.
Last time I checked this spec was Sun proprietary.

You can figure out a lot of what the sun4m specification contains
because documentation on particular implementations, such as the
SPARC classic is publically available from STB.

Generally the way it seems to work is as you move closer to newer,
higher end, machines the specs become harder to get.  If you are
willing to sign a non-disclosure agreement, and it appears to Sun
that getting the information to you will help them sell chips, things
become easier.

I didn't know any SS10 docs were publically available, but I don't
keep very close track.  Documentation on the SuperSPARC cpu used in
the SS10 has in the past been publically available from TI, but I
think TI now refers people to Sun, and I don't know if Sun still
makes it available to the general public.  If not, ask around, I think
Jim Wilson (wilson@cygnus.com) is one person with a copy.

If documentation on the SS10 is available, this would make it easier
to understand how MP works.  Although I am not sure there is all that
much you need to know.  Constructing a high quality shared memory
O/S however is extremely hard.  So hard I think it would be a mistake
to attempt.  It is fairly easy to get something simple working, but
then evolving the system in the future, and tuning it to get good real
world scaling performance is very time consuming.

Documentation on sun4d would be very hard to get.

Documentation beyond that is probably only available to companies that
are collaborating on future hardware.  An exception to this is the
64 bit SPARC v9 architecture manual which is available from Prentice-Hall.

This is pretty much everything I know, and some of which may have
changed since I last investigated.

                                                  Gordon.