Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!uflorida!gatech!amdcad!diablo!phil
From: phil@diablo.amd.com (Phil Ngai)
Newsgroups: comp.arch
Subject: Re: RISC v. CISC --more misconceptions
Message-ID: <23450@amdcad.AMD.COM>
Date: 2 Nov 88 19:46:08 GMT
References: <156@gloom.UUCP> <18931@apple.Apple.COM> <40@sopwith.UUCP> <998@l.cc.purdue.edu> <7575@aw.sei.cmu.edu>
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Reply-To: phil@diablo.AMD.COM (Phil Ngai)
Organization: Advanced Micro Devices, Inc. Sunnyvale CA
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In article <998@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes:
>There are many other operations which are cheap in hardware and expensive in
>software...I will toss in a few for starters.
>	Find the distance to the next one in a bit stream FAST.  It would

The Am29000 has a CLZ instruction which runs in one clock cycle(33 ns):

Operation: 	Determine number of leading zeros in a (32-bit) word.
Description:	A count of the number of zero-bits to the first one-bit
		in the SRCB operand is placed into the DEST location. 
		If the MSB of the SRCB operand is 1, the resulting
		count is zero. If the SRCB operand is zero, the
		resulting count is 32.




"In the West, to waste water is not to consume it, to let it flow unimpeded 
and undiverted down rivers. Use of water is, by definition, beneficial use."
(from _Cadillac Desert_)
Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or phil@amd.com