*BSD News Article 23556


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From: nate@bsd.coe.montana.edu (Nate Williams)
Newsgroups: comp.os.386bsd.questions
Subject: Re: FPU in FreeBSD?
Date: 10 Nov 1993 00:59:10 GMT
Organization: Montana State University, Bozeman  MT
Lines: 24
Message-ID: <2bpecu$mkf@pdq.coe.montana.edu>
References: <2bo8s7$c0r@nic.lth.se>
NNTP-Posting-Host: bsd.coe.montana.edu

In article <2bo8s7$c0r@nic.lth.se>, Joergen Haegg <jh@efd.lth.se> wrote:
>I noticed that some files in gcc was compiled with -NOFPU.
>Does this mean that I don't use the FPU in my 486 DX2?

This means that the current FPU emulator in *BSD is not up to snuff.  In
order to get certain programs to work with FPU/NoFPU machines, we had
to disable certain FPU features in gcc which caused problems with the
current math-emulator.  (I think they were fsin and fcos)

>What should I do to get maximum floating-point performance in FreeBSD
>and my own programs?
>Is it enough to add '-m486'?

That'll go a long way, but -m486 doesn't do any FP optimizations that I'm
aware of, just alignment optimizations in structures and data which allow
the 486 to read the stuff faster.


Nate
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