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From: kendalla@iddic.UUCP (Kendall Auel)
Newsgroups: net.arch
Subject: 286 Stack Overflow Detection
Message-ID: <2173@iddic.UUCP>
Date: Tue, 10-Sep-85 16:03:47 EDT
Article-I.D.: iddic.2173
Posted: Tue Sep 10 16:03:47 1985
Date-Received: Thu, 12-Sep-85 11:43:25 EDT
Reply-To: kendalla@iddic.UUCP (Kendall Auel)
Organization: Tektronix, Beaverton OR
Lines: 22


This is a correction/addition to my posting concerning the handling
of a stack overflow condition on the Intel 80286:

In order to switch stack segments in the midst of running a procedure,
a couple of very strict rules must be adhered to. 1) All data on the
stack may only be addressed using the "bp" register. This register
will be updated by the stack overflow exception handler. 2) At no time
may the stack pointer ("sp" register) or the "bp" register be saved
(in memory or in another register) and be assumed to be a valid address.

The main point of my original article was that a stack overflow need
not be a fatal condition on the 286, as others have stated. I have
presented one possible solution to the problem, and I suspect other
more workable solutions exist as well.


Kendall Auel
Tektronix, Inc.
Graphics Workstations Division

(These views are my own, etc...)