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From: res@ihlpl.UUCP (Rich Strebendt @ AT&T Information Systems - Indian Hill West; formerly)
Newsgroups: net.arch
Subject: Re: What I miss in micro-processors (fairly long)
Message-ID: <326@ihlpl.UUCP>
Date: Wed, 4-Sep-85 22:25:40 EDT
Article-I.D.: ihlpl.326
Posted: Wed Sep  4 22:25:40 1985
Date-Received: Fri, 6-Sep-85 05:37:28 EDT
References: <796@kuling.UUCP>
Organization: AT&T Bell Laboratories
Lines: 29

> 
>         I've been working in assembly language on micro-processors quite
> a lot recently and there are a couple of features I've been missing
> rather badly  ...  I would be very glad for views
> from other users on what kind of thing they would like to see included
> as well as some response from the people who design these things 
> 
> 1. Stack overflow detection.
>  
>   This is the one that really bugs me.  I don't know of any
> micro-processor that does this.  Why is that?  In my mind this is
> something that is badly needed, and coding the check inline would be too
> much of a performance penalty.  This is also fundamentally different
> from things like array bounds checking which, in principle, need only
> be done while debugging the program and should never appear in a
> "correct" program.  This is not true of stack overflow which can happen
> in a perfectly good program.
>   I am aware that many systems let their mmu handle the problem, but
> that doesn't seem like a very good solution to me (it doesn't check for
> stack overflow, only memory references "just above" the stack limit,
> right?) and it doesn't help at all if the system doesn't have an mmu
> (yes, all systems *should* have one, but...).

This feature is built into AT&T's WE(TM)-32100 Microprocessor.  I know,
because I just got a stack overflow exception on the other terminal
connected to a board I am developing firmware for!!  

					Rich Strebendt
					...!ihnp4!iwsl6!res