Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rice!sun-spots-request
From: TAustin.HENR801c@xerox.com
Newsgroups: comp.sys.sun
Subject: SPARCs appear to not use fsqrt
Keywords: Miscellaneous
Message-ID: <10155@brazos.Rice.edu>
Date: 23 Jul 90 21:12:46 GMT
Sender: root@rice.edu
Organization: Sun-Spots
Lines: 12
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X-Sun-Spots-Digest: Volume 9, Issue 277, message 12
Originator: spots@titan.rice.edu

I've recently been performing some instruction trace analysis on a Sun
4/110 workstation.  It seems that there is no way to generate the fsqrt
instruction from a high level language.  All square root operations are
turned into calls to _sqrt in libm.a which does not use the fsqrt
instruction.  I took the assembly output of a simple program that
calculates the square root of 2, replaced the call to _sqrt with the fsqrt
instruction and the program ran fine.  What gives?  Why doesn't anyone use
fsqrt?  It seems a significant amount of performance is being lost in
floating point intensive programs that use sqrt().

Todd Austin
taustin.henr801c@xerox.com