Article View: comp.arch
Article #12213Re: Changing IEEE rounding modes on the fly (was Re: somthing else)
From: Marvin Denman
Date: Fri, 21 Jun 1991 16:06
Date: Fri, 21 Jun 1991 16:06
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In article <3751@charon.cwi.nl> dik@cwi.nl (Dik T. Winter) writes: >In a previous posting I gave timings (from the manual) for the 88100, but >apparently the fp pipelines must be flushed before a change to the fp >control register is performed. So I was wrong, and the 88100 does not >meet the factor 3 criterion. (Alas, this is not documented, and the flush >must be programmed!) This is not true for the 88100. The floating point control register can be changed on the fly with no problems. The only flush necessary is before reading or writing the status register. The fp control register will only affect instructions issued after it is modified because its information is carried through the pipeline with it. I'm sure because I designed it that way. -- Marvin Denman Motorola 88000 Design cs.utexas.edu!oakhill!marvin
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<9106190449.AA02871@ucbvax.Berkeley.EDU> <1991Jun19.165150.2121@shinobu.sgi.com> <3751@charon.cwi.nl>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!cs.utexas.edu!oakhill!marvin From: marvin@oakhill.sps.mot.com (Marvin Denman) Newsgroups: comp.arch Subject: Re: Changing IEEE rounding modes on the fly (was Re: somthing else) Message-ID: <1991Jun21.160606.4247@oakhill.sps.mot.com> Date: 21 Jun 91 16:06:06 GMT References: <9106190449.AA02871@ucbvax.Berkeley.EDU> <1991Jun19.165150.2121@shinobu.sgi.com> <3751@charon.cwi.nl> Reply-To: marvin@bushwood.UUCP (Marvin Denman) Organization: Motorola Inc., Austin, Texas Lines: 20