Article View: comp.arch
Article #10691Re: Vector vs Cache/Superscalar
From: Jim Giles
Date: Tue, 07 May 1991 22:46
Date: Tue, 07 May 1991 22:46
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1223 bytes
In article <23348@lanl.gov>, jlg@cochiti.lanl.gov (Jim Giles) writes:
|> [...]
|>
|> DO 30 i = j+1, N
|> A(i) = A(i) + A(i-j)
|> 30 continue
Whoops! I just realized I still have a dependency here! That's what I get
for reading articles on functional programming just before a Fortran-like
posting.
The '30' loop should be replaced with the two loops below:
DO 30 i = j+1, N
temp(i) = A(i) + A(i-j)
30 continue
DO 40 i = j+1, N
A(i) = temp(i)
40 continue
These vectorize and eliminate the dependency. It's all so much simpler in
a language with whole array syntax!
Sorry for the inconvenience.
J. Giles
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<1991May4.031835.7979@midway.uchicago.edu> <1991May6.035310.26794@marlin.jcu.edu.au> <11921@mentor.cc.purdue.edu> <23348@lanl.gov>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!paperboy!hsdndev!cmcl2!lanl!cochiti.lanl.gov!jlg From: jlg@cochiti.lanl.gov (Jim Giles) Newsgroups: comp.arch Subject: Re: Vector vs Cache/Superscalar Message-ID: <23353@lanl.gov> Date: 7 May 91 22:46:58 GMT References: <1991May4.031835.7979@midway.uchicago.edu> <1991May6.035310.26794@marlin.jcu.edu.au> <11921@mentor.cc.purdue.edu> <23348@lanl.gov> Sender: news@lanl.gov Organization: Los Alamos National Laboratory Lines: 27