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From: jorgense@irisa.fr (Finn Jorgensen)
Newsgroups: comp.os.msdos.programmer
Subject: Re: 8088 vs 8086
Message-ID: <1991Jun24.160522.23342@irisa.fr>
Date: 24 Jun 91 16:05:22 GMT
References: <1991Jun21.030948.10951@cs.mcgill.ca> <1991Jun21.173218.1912@mccc.edu> <2601@gold.gvg.tek.com>
Sender: news@irisa.fr
Reply-To: jorgense@irisa.fr (Finn Jorgensen)
Organization: Irisa, Rennes(FR)
Lines: 21

To answer the question from Shaun Case about self modifying code :

One way (the only, to my knowledge) to test wether you have a '88 or a '86
is to modify code five bytes after the program counter. If the processor 
executes the modified code, it is a '88 (the modified code has not been
fetched yet) if the original code (ie. before modification) is executed,
you have a '86 (code already in prefetch queue before modification).

The same test, using an adress slightly further down, can be used to
distinguish the '88-'86 family from the later processors.

Anyway, self-modifying code has always been considered very dangerous and
bad practice. It is even more so with these prefetching processors.

Greetings from Brittany, France !

Finn Jorgensen. 
IFSIC, Universite de RENNES I
Campus de Beaulieu
35042 RENNES CEDEX
FRANCE