Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!bu.edu!rpi!zaphod.mps.ohio-state.edu!uwm.edu!bionet!agate!linus!linus!bs From: bs@linus.mitre.org (Robert D. Silverman) Newsgroups: comp.arch Subject: Re: F.P. vs. arbitrary-precision (was: Killer Micro II) Message-ID: <119879@linus.mitre.org> Date: 12 Sep 90 15:15:46 GMT References: <3755@osc.COM> <4513@taux01.nsc.com> <119244@linus.mitre.org> <1990Sep10.215549.26260@uncecs.edu> Reply-To: bs@gauss.UUCP (Robert D. Silverman) Organization: The MITRE Corporation, Bedford MA Lines: 29 In article <1990Sep10.215549.26260@uncecs.edu> urjlew@uncecs.edu (Rostyk Lewyckyj) writes: :In article <119244@linus.mitre.org>, bs@linus.mitre.org (Robert D. Silverman) writes: :> The four basic operations of arithmetic are +, -, x, /. Any computer that :> can't perform them on its atomic data units [whatever the word size is] :> is a joke. : : :If the basic unit for representing a number is a word, then to handle :the product of two numbers you may well need a double word. But then :you must provide operations to handle double words. So then the double :word becomes a basic unit, and so on ad infinitum. If in addition to What is needed is simply a single, temporary double word. Typically after forming a double word product it is then reduced to a single word. e.g. compute AB/C, AB mod C, etc. In any event, your response adresses LANGUAGE issues, not hardware. I'm quite happy to work in assembler to handle double length registers as long as the HARDWARE provides the capability. Note that for language purposes one could provide an in-line routine to multiply two words and return the upper/lower halves. Similarly a division routine could take the two halves and divide by a third number. -- Bob Silverman #include Mitre Corporation, Bedford, MA 01730 "You can lead a horse's ass to knowledge, but you can't make him think"