Article View: comp.arch
Article #11947Re: new instructions
From: herrickd
Date: Tue, 04 Jun 1991 16:30
Date: Tue, 04 Jun 1991 16:30
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1297 bytes
In article <182@armltd.uucp>, abaum (Allen Baum) writes: > In article <12947@mentor.cc.purdue.edu> hrubin@pop.stat.purdue.edu (Herman Rubin) writes: > [much omitted throughout the quotations] >>This points out another reason for cheap instructions at little cost. >> >>Now how much additional silicon would it take to provide both signed >>and unsigned? > > Do not presume that because > unsigned & signed multiply are both multiplies, that including both > is cheap. It may not be the case. Boothe style mults. are implicitly > signed, for example. To pretend they aren't mean multiplying two > 33 bit numbers. What fantastic advantage does one derive from using "Boothe style mults." that makes up for losing unsigned arithmetic. This sounds to me like the reason for not using them in a general purpose computer. dan herrick herrickd@iccgcc.decnet.ab.com
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!abvax!iccgcc!herrickd From: herrickd@iccgcc.decnet.ab.com Newsgroups: comp.arch Subject: Re: new instructions Message-ID: <4780.284b79e4@iccgcc.decnet.ab.com> Date: 4 Jun 91 16:30:44 GMT References: <12947@mentor.cc.purdue.edu> <182@armltd.uucp> Distribution: comp Lines: 21