Article View: comp.arch
Article #12493Re: Swap byte instruction - how high is the win?
From: Dan Prener
Date: Fri, 08 Jan 1993 04:35
Date: Fri, 08 Jan 1993 04:35
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1451 bytes
In article <1993Jan7.074052.19620@qb.rhein-main.de> vhs@rhein-main.de (Volker Herminghaus-Shirai) writes:
> Subject line almost says it all. Many modern processors have an
> instruction to swap the bytes in a word. Can one quantify the
> win of using this instruction vs. the equivalent sequence of
> instructions? How much silicon is needed? What applications
> win the most and how much? There must be *some* resaon why the
> RISC folks put it in, right?
The win is approximately zero for general code. But it is significant
for emulating a processor with the opposite byte order.
--
Dan Prener (prener@watson.ibm.com)
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Newsgroups: comp.arch Path: arc1-ca.pugleaf.net!sparky!uunet!paladin.american.edu!howland.reston.ans.net!usc!sdd.hp.com!saimiri.primate.wisc.edu!ames!agate!linus!philabs!acheron!scifi!watson!yktnews!admin!yktnews!prener From: prener@watson.ibm.com (Dan Prener) Subject: Re: Swap byte instruction - how high is the win? Sender: news@watson.ibm.com (NNTP News Poster) Message-ID: <PRENER.93Jan7233525@prener.watson.ibm.com> In-Reply-To: vhs@rhein-main.de's message of Thu, 7 Jan 93 07:40:52 GMT Date: Fri, 8 Jan 1993 04:35:25 GMT Disclaimer: This posting represents the poster's views, not necessarily those of IBM References: <1993Jan7.074052.19620@qb.rhein-main.de> Nntp-Posting-Host: prener.watson.ibm.com Organization: IBM T.J. Watson Research Center, Hawthorne, New York Lines: 13