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From: hadeishi@husc4.harvard.edu (mitsuharu hadeishi)
Newsgroups: net.micro.amiga
Subject: Re: Floating point libraries
Message-ID: <417@husc6.HARVARD.EDU>
Date: Thu, 16-Oct-86 14:43:51 EDT
Article-I.D.: husc6.417
Posted: Thu Oct 16 14:43:51 1986
Date-Received: Thu, 16-Oct-86 23:02:17 EDT
References: <8610160630.AA06315@cory.Berkeley.EDU>
Sender: news@husc6.HARVARD.EDU
Reply-To: hadeishi@husc4.UUCP (mitsuharu hadeishi)
Organization: Harvard Science Center
Lines: 33
Summary: More accurate info

In article <8610160630.AA06315@cory.Berkeley.EDU> dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>	I believe Manx allows you to use the FFP and IEEE rt-libraries via
>float/double declarations.  W/ Lattice , you have to make the calls manually.
>Manx wins hands-down on floating point operations.  From the sorry state
>Lattice's math library is in, it looks like they simply ported it from
>the IBM (or other) version... extremely slow.

	Actually the old Manx uses FFP only.  This makes Manx fast,
but inaccurate.  Also FFP mathtrans.library doesn't support all of
the transcendental functions that are available in most IEEE
implementations; I'm not sure which functions aren't implemented.
(FFP is only 32 bits, singel precision only.)

	The next release of Manx will have options to use FFP, IEEE,
68881 IEEE, and perhaps some others.

	The old Lattice uses IEEE but converted all arguments
to double precision before doing computations.  The algorithms
were also very slow and unoptimized.  Thus old Lattice IEEE was about
five to ten times slower than FFP.  However, it was a lot more
accurate than FFP and also provided the full gamut of transcendental
functions.

	However, the new release of Lattice C contains a floating
point library which is IEEE but is reputed to be about five times
faster or more.  This makes it competitive with FFP, and also
the data will be compatible with the 68881 (a VERY large plus for
portability of floating point data between applications and machines.)
Overall I would prefer to use the new Lattice fast IEEE libraries
(highly optimized) over FFP since FFP is nonstandard (will not work
with the 68881) and only works in single precision.

				-Mitsu