Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: utzoo!linus!decvax!decwrl!sun!gnu 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.