Path: utzoo!utgpu!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!claris!apple!baum
From: baum@Apple.COM (Allen J. Baum)
Newsgroups: comp.arch
Subject: Re: Population count instruction (was Re: RISC v. CISC ...)
Message-ID: <19915@apple.Apple.COM>
Date: 3 Nov 88 18:38:18 GMT
References: <1622@scolex> <1854@eos.UUCP>
Reply-To: baum@apple.UUCP (Allen Baum)
Organization: Apple Computer, Inc.
Lines: 21

[]
>In article <1854@eos.UUCP> jaw@eos.UUCP (James A. Woods) writes:
>Seymour Cray was asked about the motivation for this op code, and said,
>without further elaboration -- "The NSA made me do it." 
>When one realizes that an XOR of two words followed by population count
>yields Hamming distance, allegedly very important in crypto work,
>this makes sense.
>
>Even more eyebrow raising is the related AVL (additional vector logical)
>unit available for certain Cray serial numbers, which amplifies tricks like
>the above by sixty-four.  This second logical vector unit, again
>an NSA-only custom add-on device, might also help such a machine play
>a mean game of chess, but that's a different conspiracy theory ...

Do you have any references to the AVL? This is the first I've heard of it.
This sounds very similar to the HARVEST co-processor for the IBM-STRETCH,
again, developed with NSA funds. For those of you that want to know what the
ultimate in CISC is, you should take a look at this machine!
--
		  baum@apple.com		(408)974-3385
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