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From: jack@cwi.nl (Jack Jansen)
Newsgroups: comp.sys.nsc.32k
Subject: MMU question.
Message-ID: <14@piring.cwi.nl>
Date: Fri, 24-Jul-87 04:57:21 EDT
Article-I.D.: piring.14
Posted: Fri Jul 24 04:57:21 1987
Date-Received: Sat, 25-Jul-87 13:38:18 EDT
Organization: AMOEBA project, CWI, Amsterdam
Lines: 17
Keywords: Page tables, EIA register.


Well, every time I change something in my MMU code, I get bit by this,
and usually the problem dissapears after some hacking, but now I would
like to get rid of this once and for all:

If you change a secondary page table entry, should you invalidate the
entry (by putting the address in the EIA) *before* or *after* modifying
the in-core entry? I.e. does the MMU just forget about the SPT entry, or
does it write it back to main memory before it does?
And, the same question, but now for changing PTB1.

The system I'm working on is based on a 32016 and a 32082, but given National's
fantastic upwards compatability, that shouldn't make much of a difference,
I guess.
-- 
	Jack Jansen, jack@cwi.nl (or jack@mcvax.uucp)
	The shell is my oyster.