Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site hammer.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!genrad!decvax!tektronix!orca!hammer!steveg From: steveg@hammer.UUCP (Steve Glaser) Newsgroups: net.micro.68k,net.micro.16k Subject: Re: PDP11s vs the micros Message-ID: <1425@hammer.UUCP> Date: Mon, 5-Aug-85 21:58:33 EDT Article-I.D.: hammer.1425 Posted: Mon Aug 5 21:58:33 1985 Date-Received: Sat, 10-Aug-85 04:43:39 EDT References: <1617@hao.UUCP> <847@mako.UUCP> <2422@sun.uucp> <2994@nsc.UUCP> <2506@sun.uucp> <877@mako.UUCP> <2547@sun.uucp> Reply-To: steveg@hammer.UUCP (Steve Glaser) Organization: Tektronix, Wilsonville OR Lines: 23 Xref: linus net.micro.68k:981 net.micro.16k:329 The "p-machine" garbage for the 32xxx was probably just early marketing hype. It's real difficult to sell anything in a big company unless you hang it on something familiar. The "p-machine" is an old system that was probably familiar to somebody in charge at the time. Remember that there was a chip known as the 16016 in the family. That was a 16032 (aka 32016 nowdays) with Intel 8080 emulation mode added (not Z-80, just 8080). (Gee you could write a CP/M emulator.) This should give you some insight into their thinking at the time. (No I wasn't there, but I was an early user of the chipset). As for eliminating auto +/- addressing mode, I support that decision. Given their decision to "back out" instructions that get page faults rather than dump out the internal microstate like the 68010, National would have to keep shadow copies of too much internal stuff around in case a page fault came through. That's a big hassle and takes chip real estate. I think having full memory to memory addressing is more useful that auto +/-, especially for compiler generated code. (well maybe not for pcc -- it's model seems to be put something in a register, munch on it, put it back in memory). Steve Glaser steveg.tektronix@csnet-relay.arpa or tektronix!steveg