From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.3 required=5.0 tests=BAYES_00,INVALID_MSGID, MSGID_RANDY autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a30e9cc47b5029fe X-Google-Attributes: gid103376,public From: Robert Dewar Subject: Re: ratioanl number type Date: 1999/12/14 Message-ID: <836b5a$m2m$1@nnrp1.deja.com>#1/1 X-Deja-AN: 560621281 References: <38473D8A.9BB68676@gte.net> <3847E5B3.B96339A8@iforex.net> <385252FF.BB4C7A5@gte.net> <01bf43ea$646d5bc0$022a6282@dieppe> <38527A46.B4833D6A@gte.net> <01bf43f3$3aadb600$022a6282@dieppe> <82upl4$dra$1@nnrp1.deja.com> X-Http-Proxy: 1.0 x27.deja.com:80 (Squid/1.1.22) for client 202.135.78.207 Organization: Deja.com - Before you buy. X-Article-Creation-Date: Tue Dec 14 21:00:30 1999 GMT X-MyDeja-Info: XMYDJUIDrobert_dewar Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/4.04 [en] (OS/2; I) Date: 1999-12-14T00:00:00+00:00 List-Id: In article , "Vladimir Olensky" wrote: > This technique was used for more than 20 years in Russian > supercomputers "Elbrus". So no wonder that one of the > leading scientists from "Elbrus" team (Pentkovsky) was invited > to the Intel and he lead the development of SIMD extensions > for Intel chips. Well there is absolutely nothing new conceptually in the SIMD extensions (or in the Elbrus), these techniques are very old and very well known and have been for 30 years. Indeed the jury is still out on whether such extensions are worthwhile. The ia64 should help to answer that question. Remember that the Elbrus team as well as similar contemporary architectures were very much under the CISC philosophy (and of course Intel still is, indeed I would really call the ia64 a CISC design, full of crufty stuff [e.g. long offset arithmetic available only in 4 of the 128 registers]. So the point is not the general approach, but rather, specificaly for the ia32 extensions: a) whether it is useful in the context of an optimizing Ada compiler. Answer: very dubious, almost certainly there is a long list of better optimization opportunities for any existing compiler. Obviously you can find some test cases where pattern matching will do nice things, but I doubt as a general optimization it will have a noticable affect on applications in general. b) Whether it would help a hand written multi-precision integer package. Again I think dubious. Vladimir, assuming you have some experience with multi-precision arithmetic packages, why not try writing some critical inner loops, and timing them both ways. Vague conjecture here is not very convincing :-) Sent via Deja.com http://www.deja.com/ Before you buy.