Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site kitty.UUCP Path: utzoo!watmath!sunybcs!kitty!peter From: peter@kitty.UUCP (Peter DaSilva) Newsgroups: net.micro.68k,net.micro.16k Subject: Re: Re: PDP11s vs the micros Message-ID: <273@kitty.UUCP> Date: Thu, 8-Aug-85 09:49:28 EDT Article-I.D.: kitty.273 Posted: Thu Aug 8 09:49:28 1985 Date-Received: Fri, 9-Aug-85 04:40:56 EDT References: <1617@hao.UUCP> <847@mako.UUCP> <2422@sun.uucp> Organization: Recognition Research Corp., Clarence, NY Lines: 25 Xref: watmath net.micro.68k:1042 net.micro.16k:360 > 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 Any particular reason to do this rather than restart the instruction from where it left off? I hadn't heard of this approach... what does the Vax do? What are the tradeoffs. > 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). main(ac, av) register int ac; register char **av; { while(*++av) { ... } } Not an uncommon case construction in 'C'.