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Article #10469Re: Bitfield instructions--a good idea?
From: Andrew John Williams
Date: Fri, 26 Apr 1991 14:09
Date: Fri, 26 Apr 1991 14:09
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Not really anything to do with this - but hows this for 'orrible... I picked up the 1980 Nat Semi MOS book recently, and had a look at the COPS420 (or whatever it was) specs. No shift instruction. The way they suggested was to swap the accumulator out to the shift register (also connected to the outside world) and wait. The shift register was syncronised to the instruction cycle, so to shift one bit you swapped A back in the next instruction. For a 2 bit shift, you inserted a NOP (or other such useful instruction). Don't worry though - the maximum delay was 4 instructions, 'cos thats how big A was. And people complain about the 8086! John West (stealing Andrew's account) Do fish need aqualungs?
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arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!munnari.oz.au!uniwa!andrewwReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!munnari.oz.au!uniwa!andreww From: andreww@uniwa.uwa.oz (Andrew John Williams) Newsgroups: comp.arch Subject: Re: Bitfield instructions--a good idea? Message-ID: <1991Apr26.140902.18773@uniwa.uwa.oz> Date: 26 Apr 91 14:09:02 GMT References: <1991Apr15.193425.3436@waikato.ac.nz> <712@seqp4.UUCP> Organization: University of Western Australia Lines: 13