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From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
To: stevenj AT alum DOT mit DOT edu, djgpp AT delorie DOT com
Subject: Re: ANNOUNCE: DJGPP port of FFTW 3.1 uploaded
Date: Fri, 3 Feb 2006 13:58:54 +0100
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Am Freitag, 3. Februar 2006 03:38 schrieben Sie:
> Juan Manuel Guerrero wrote:
> >     To make the package good for all djgpp installations, I have disabled all
> >     processor specific instruction set optimizations. This may make the library
> >     a little bit slower on modern processors but this produces smallest
> >     libraries and the programms linked against the library will work on all
> >     processors platforms.
> 
> This is not necessary.  If you compile FFTW for SSE/SSE2, it checks at
> runtime whether those instructions are supported on the current
> processor.  If not, it disables the SSE code.  So, the library is
> portable even if it uses SSE.  (This is exploited by Linux
> distributions of FFTW, Matlab, etcetera.)
> 
> If you are using FFTW's configure script, you should use
> --enable-portable-binary to prevent it from using -march.  If you are
> compiling "manually" for some reason you will need to be careful which
> files you compile with -msse/-msse2.
> 
> See also the FFTW manual.
> 
> Regards,
> Steven G. Johnson

Thank you for the clarifications. To configure the sources using djgpp, the
configure script distributed with fftw is used so it will be easy to produce
portable libraries on DOS as you described.
Will take care about all this the next time I upload a new version of the port.
Neatherless I will copy the message you send me to the comp.os.msdos.djgpp
group for the convenience of all users. Hope it is ok with you.

Regards,
Juan M. Guerrero