Subject: Re: somebody mentioned SMP...
To: Chuck Van Tilburg <>
From: James da Silva <jds@cs.UMD.EDU>
List: current-users
Date: 08/10/1995 16:30:53
 > Is there any industry standard and interest in, or plans for SMP 
 > (really) with NetBSD on Intel (or other platforms)?  At least with the 
 > Intel PC platform it makes little sense to proceed without some kind of
 > standard.  Probably a per-platform standard is the way it is, but can
 > we get the specs?

The Intel MP Spec 1.1 is available for free from Intel - you can just call
them up and ask them for it.  It is also available online as a postscript
file from their web site.  Try poking around until
you find it.

This document, along with the Pentium processor manual section on the Local
APIC, has information sufficient to get the second processor of a dual
pentium up and running.

If you want to reprogram the IO APIC (not necessary unless you want to
share interrupts between processors), you need more docs.  I'm not sure
where the IO APIC for Pentium chipsets is documented, but to be compatible
with the MP spec, the IO APIC should be upward compatible with the 82489DX,
which is documented somewhere in the Intel i486 book series (my docs are at

Also, the Mindshare Pentium Arch book talks about the local APIC and dual
pentiums, but I doubt it's sufficient by itself to actually code something
up.  It might help the learning curve, though, because Intel's MP chapter
in the pentium book doesn't do a good job of explaining how to use the
APIC, it just documents all the registers.  Or you could just keep reading
the Intel docs over and over again until it clicks...

:  James da Silva  :  UMCP Computer Science Dept  :          RIP          :
:  :  :         Jerry         :