Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!newstop!exodus!exodus-bb!khb From: khb@chiba.Eng.Sun.COM (Keith Bierman - SPD Advanced Languages) Newsgroups: comp.arch Subject: Re: Why FP at all? (was: Re: Killer Micro II) Message-ID: Date: 7 Sep 90 17:36:18 GMT References: <527@llnl.LLNL.GOV> <603@array.UUCP> <2482@l.cc.purdue.edu> <1632@lhr.Morgan.COM> Sender: news@exodus.Eng.Sun.COM Organization: Sun MegaSystems Lines: 31 In-reply-to: stephen@estragon.uchicago.edu's message of 7 Sep 90 03:59:28 GMT In article stephen@estragon.uchicago.edu (Stephen P Spackman) writes: ... All I'm thinking is that an FPU *may not* be the best answer. It's 1990 now; we can rely on the compiler. Language-driven architecture is dead (though language-tuned architecture is another story). Semantic gap is, if not a myth, then a strength - compilers need elbowroom in which to optimise. Is it so absurd to suggest that outside of the supercomputer market, ... It isn't absurd to think about it. The literature contains such thoughts over the years, going back at least 15 years. Probably more. The consensus view of those who cast the little bugger though, has so far been that this isn't a good idea. Often folks employ the heuristic that any instruction which gets used frequently, say 3+% of the time has certainly earned its keep. FP instructions satisfy that. There are all sorts of other data points also. Go, formalize your proposal, gather statistics from "real" programs (spec, perfect club, US steel, etc.) using both the conventional and your special compiler (and possibly other candiate special compilers) on a variety of machines and publish the results and your conclusion. -- ---------------------------------------------------------------- Keith H. Bierman kbierman@Eng.Sun.COM | khb@chiba.Eng.Sun.COM SMI 2550 Garcia 12-33 | (415 336 2648) Mountain View, CA 94043