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From: jans@orca.UUCP (Jan Steinman)
Newsgroups: net.arch
Subject: Re: Re: Where to do stack checking, etc.
Message-ID: <1744@orca.UUCP>
Date: Thu, 19-Sep-85 13:38:26 EDT
Article-I.D.: orca.1744
Posted: Thu Sep 19 13:38:26 1985
Date-Received: Sat, 21-Sep-85 06:12:58 EDT
References: <796@kuling.UUCP> <1713@orca.UUCP> <1599@peora.UUCP> <335@ihlpl.UUCP> <2384@uvacs.UUCP>
Reply-To: jans@orca.UUCP (Jan Steinman)
Organization: Tektronix, Wilsonville OR
Lines: 23
Summary: 

In article <2384@uvacs.UUCP> mac@uvacs.UUCP (Alex Colvin) writes:
>>> 1) The ability to trap when JUST ONE particular address was generated as a
>>> data reference.  
>
>The Honeywell... mainframes also have this ability, ... but since the
>address is absolute, it's not much use to time-sharing users.
>
>I'm still looking for a machine that will trap references to uninitialized
>data.

(I still stand by my statement that such things belong in the (either on or
off chip) MMU.)

The NS32000 MMU has two registers for reference breakpointing.  These can be
set up for either data or program, initialized or not, as either physical or
virtual addresses.  I used them heavily for debugging a reference counting
garbage collector.  (Alright!  Who set that reference count to -1!)
Unfortunately, the reference breakpoints are broken on the latest mask.
8
-- 
:::::: Artificial   Intelligence   Machines   ---   Smalltalk   Project ::::::
:::::: Jan Steinman		Box 1000, MS 61-405	(w)503/685-2956 ::::::
:::::: tektronix!tekecs!jans	Wilsonville, OR 97070	(h)503/657-7703 ::::::


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