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 autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,dec0a6ed5b5044de X-Google-Attributes: gid103376,public From: robert_dewar@my-dejanews.com Subject: Re: Code portability question Date: 1999/01/25 Message-ID: <78gem9$imp$1@nnrp1.dejanews.com>#1/1 X-Deja-AN: 436468405 References: <36A94B78.963F3215@wvu.edu> <36A9849C.A9FE01E4@rocketmail.com> <36AABFAA.2D844356@wvu.edu> <36AB878E.F51CA837@rocketmail.com> X-Http-Proxy: 1.0 x1.dejanews.com:80 (Squid/1.1.22) for client 205.232.38.14 Organization: Deja News - The Leader in Internet Discussion X-Article-Creation-Date: Mon Jan 25 00:42:51 1999 GMT Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/4.04 [en] (OS/2; I) Date: 1999-01-25T00:00:00+00:00 List-Id: In article <36AB878E.F51CA837@rocketmail.com>, Corey Ashford wrote: > > that the K6 handled floats so differently that it > > messed up his program. I didn't see how this was > > possible. Or does Ada now discriminate against the > > AMD? > > Not unless your compiler emits code for the AMD/Cyrix > 3DNow instructions! (not likely) > > The AMD processor is supposed to be an exact clean-room > implementation of the > IA32 architecture (plus their 3D enhancements). > > I think the chances of the problem being due to a > difference in the floating point register implementation > are about, as you surmised, zero. Wait a moment! This is going in a bizarre direction. It is' OF COURSE the case that the K6 (and any other ia32 implementation) has radically different floating-point behavior, namely it implements 80-bit floating-point formats which are typically used for intermediate values. It would be quite possible to create an algorithm that was stable on the ia32 and unstable on a 64-bit Unix implementation, and this is possible even if all the declared variables are float and long_float (remember these types are unconstrained in Ada 95, so they can use the 80-bit format at the compiler's discretion). I think this is unlikely, but it is a WHOLE lot more likely than worrying about the AMD 3-D instructions! -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own