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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!uakari.primate.wisc.edu!unmvax!unmvax.cs.unm.edu!4rst
From: 4rst@unmvax.cs.unm.edu (Forrest Black)
Newsgroups: comp.arch,comp.misc
Subject: LoadAll?
Message-ID: <597@unmvax.unm.edu>
Date: 27 Dec 89 22:59:02 GMT
Sender: 4rst@unmvax.unm.edu
Reply-To: 4rst@unmvax.cs.unm.edu (Forrest Black)
Distribution: usa
Organization: n. The process of getting new organs.
Lines: 37


Hello!  I'm looking for information on the undocumented 80[2,3]86 LOADALL
instruction.  I think maybe the information I'm looking for passed by on
the net a while back, but that must have been before I started reading news.
I have had a hard time getting any concrete information on this matter, so
it's time to turn to all you netlanders for help!  Here's what I do know:

  o   The instruction is encoded (0fh 05h) on 286, and (0fh 07h) on 386.
  o   The instruction is supposed to load some or all of the machine state
      from a table in low memory (0080h:0000h).
  -   I have verified the above.  I put a tell-tale pattern at 80:0, and some
      of the registers had pieces of the pattern in them when I managed to
      regain control (I put a handler on the illegal instruction trap).
  o   The instruction is reportedly a diagnostic tool reserved by Intel, but
      some software houses have used it in applications (rumor).

What I would like to know:

  ?   The format of this table in low memory.
  ?   Whether a complementary instruction STOREALL exists.
  ?   The real purpose behind this bizarre instruction.

If anybody out there can help me, it would be greatly appreciated!
Thanks in advance.  Please e-mail:

4rst@doc.cs.unm.edu     or   ...{ucbvax,gatech,rice}!unmvax!4rst

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