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Article #10243Re: Mac of the 90's: FLOPS, MegaFLOPS?
From: Lawrence D'Oliveiro
Date: Mon, 22 Jan 1990 06:01
Date: Mon, 22 Jan 1990 06:01
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In <5338.25af60d1@jane.uh.edu>, math1h3@jane.uh.edu (David Wagner), in a list of wishes for the numeric capabilities of future Macintoshes, asks for "support for single-precision and double precision arithmetic and transcendental functions in whatever coprocessor is used. It seems terribly wasteful to always do extended precision arithmetic and transcendental functions when the user/programmer might only want or need single precision." That's as may be, but if you don't compute the intermediate results to the maximum precision available, the final answers you get will be even less accurate than you're used to. The IEEE 754 standard demands that all arithmetic be carried out to extended precision. Both the numeric coprocessor families for which I have information (68881/68882, 80x87) work this way. Because of this, it's actually *faster* to all the arithmetic in your program in extended precision, and only convert to/from external formats when inputting values, or outputting results.
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<1990Jan22.060142.25577@peace.waikato.ac.nz>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!munnari.oz.au!comp.vuw.ac.nz!kaukau.comp.vuw.ac.nz!waikato!ldoReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!munnari.oz.au!comp.vuw.ac.nz!kaukau.comp.vuw.ac.nz!waikato!ldo From: ldo@peace.waikato.ac.nz (Lawrence D'Oliveiro) Newsgroups: comp.sys.mac Subject: Re: Mac of the 90's: FLOPS, MegaFLOPS? Summary: One of your wishes you don't want Keywords: IEEE 754, numeric precision Message-ID: <1990Jan22.060142.25577@peace.waikato.ac.nz> Date: 22 Jan 90 06:01:42 GMT References: <5338.25af60d1@jane.uh.edu> Organization: University of Waikato, Hamilton, New Zealand Lines: 18