Article View: comp.arch
Article #1904Re: John von Neumann, sqrt instr
From: Hank Dietz
Date: Sun, 20 Aug 1989 17:02
Date: Sun, 20 Aug 1989 17:02
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1547 bytes
In article <3312@blake.acs.washington.edu> lgy@newton.phys.washington.edu (Laurence Yaffe) writes: ... >2) I'm content if divide is (typically) no more than 5 times slower > than multiply. Most of my programs probably wouldn't care if > divide was 100 times slower than multiply, but that's not good > enough - a few of my important programs do need a better divide. ... >5) I'm not a big user of square roots. As long as square roots cost > less than 100 multiplies, I don't think I'd trade faster square roots > for slower performance in other ops. .... Doing this all in software (and restricting ourselves to integer for simplicity), we managed to get divide to be FASTER than multiply... but it doesn't give you modulus/remainder for free. Yeah, it surprised me too. I still haven't been able to find a software technique to make square root comparably fast. Anybody got a screamer of a software technique for computing square root? -hankd@ecn.purdue.edu
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!purdue!mentor.cc.purdue.edu!pur-ee!hankd From: hankd@pur-ee.UUCP (Hank Dietz) Newsgroups: comp.arch Subject: Re: John von Neumann, sqrt instr Message-ID: <12640@pur-ee.UUCP> Date: 20 Aug 89 17:02:59 GMT References: <21353@cup.portal.com> <25643@obiwan.mips.COM> <1513@l.cc.purdue.edu> <2376@wyse.wyse.com> <3312@blake.acs.washington.edu> Reply-To: hankd@pur-ee.UUCP (Hank Dietz) Distribution: na Organization: Purdue University Engineering Computer Network Lines: 20