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From: gnu@sun.uucp (John Gilmore)
Newsgroups: net.micro.68k
Subject: Re: detecting processor type (68000/68010/etc) in software?
Message-ID: <1769@sun.uucp>
Date: Thu, 1-Nov-84 17:34:33 EST
Article-I.D.: sun.1769
Posted: Thu Nov  1 17:34:33 1984
Date-Received: Sat, 3-Nov-84 06:03:30 EST
References: <368@foros1.UUCP> <1753@sun.uucp> <217@rlgvax.UUCP>
Organization: Sun Microsystems, Inc.
Lines: 11

> > I know of no way for user code to distinguish a 68000 from a 68008
> > or 68010 or 68012.
> Why won't trying to execute an RTD instruction separate the 68010s from
> the 68000/68008s?

The trap caused by attempting RTD on a 68000 cannot be caught by *user*
code.  It takes cooperation from the supervisor.

I believe that an unrolled move loop is faster than a one-instruction
dbcc loop anyway, on all 68000 family chips.  The one-instruction loop
is just more convenient, e.g for a compiler to generate.