Re: RISC is NOT micro-code

Article View: comp.arch

Article #1624

#1624

From: Gideon Yuvall
Date: Fri, 21 Jul 1989 21:03

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In article <43004@bbn.COM> slackey@BBN.COM (Stan Lackey) writes:
>2. Rounding modes.  No compiler on Earth uses them, other than to get
>around instruction set deficiencies (rounding when converting from
>FP to integer).  This particular problem is more efficiently solved by
>adding a second version of the convert-to-integer instruction.
>
>Their use has been intended for range arithmetic.  Now, when I asked,
>lots of people knew what they were for, but no one [on comp.arch] had
>ever heard of them having ever been used.  Interesting how much
... ...

K.C.Ng's square-root code (part of 4.3BSD; look under
the "#if 0" conditional) uses rounding modes to compute correct
SQRTs.
-- 
Gideon Yuval, gideony@microsof.UUCP, 206-882-8080 (fax:206-883-8101;TWX:160520)

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<753@bnr-fos.UUCP> <1989Jul17.035238.6497@utzoo.uucp> <756@bnr-fos.UUCP> <2203@taux01.UUCP> <42942@bbn.COM> <23659@winchester.mips.COM> <43004@bbn.COM>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!microsoft!gideony
From: gideony@microsoft.UUCP (Gideon Yuvall)
Newsgroups: comp.arch
Subject: Re: RISC is NOT micro-code
Message-ID: <7033@microsoft.UUCP>
Date: 21 Jul 89 21:03:28 GMT
References: <753@bnr-fos.UUCP> <1989Jul17.035238.6497@utzoo.uucp> <756@bnr-fos.UUCP> <2203@taux01.UUCP> <42942@bbn.COM> <23659@winchester.mips.COM> <43004@bbn.COM>
Reply-To: gideony@microsoft.UUCP (Gideon Yuvall)
Organization: Microsoft Corp., Redmond WA
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