Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!tut.cis.ohio-state.edu!rutgers!cbmvax!martin
From: martin@cbmvax.commodore.com (Martin Hunt)
Newsgroups: comp.sys.amiga
Subject: Re: Manx5.0: large code, wrong answers?
Keywords: Manx5.0, c language
Message-ID: <10337@cbmvax.commodore.com>
Date: 25 Mar 90 02:38:54 GMT
References: <8080@tank.uchicago.edu>
Reply-To: martin@cbmvax (Martin Hunt)
Distribution: na
Organization: Commodore, West Chester, PA
Lines: 40

> I finally received my copy of Manx5.0, and I have been testing it out
> by recompiling and rerunning some old programs.  Results have been
> worrisome.  With one small program, I get the correct answer with
> Manx3.4 (checked by hand and checked by compiling the same code on an
> Elexsi and a Sun 3), but an answer that is precisely a factor of 100	
> smaller with Manx5.0.  How can this be???

I had not yet checked out floating point on Manx 5.0, so I compiled
your program with it and with Lattice 5.05.  Both compilers gave correct
answers.

> By the way, the code is almost exactly a factor of 2 larger with
> Manx5.0; even though the version with 3.4 was compiled with +L option
>and linked to -lm32 -lc32.  (The Manx5.0 version is about 40% larger
>than the Elexsi version.)  What is happening here?  Are we to conclude
>that 5.0 gives larger code and wrong answers?

By default, Manx 5.0 uses Manx IEEE format which includes support for
long doubles.  This porbably accounts for the size increase.

Here are my results.

Compiler        Math library           Executable size
Manx              IEEE                  9492
Manx             Manx IEEE             14068
Manx             68881                  8712
Lattice           IEEE                 11256
Lattice           68881                12020
Lattice           FFP                  10236

Nothing unusual here.  If you don't want large executables and you're
only using floating point, don't use the Manx IEEE library.

Sorry this wasn't much help.  Are you sure you compiled and linked with the correct floating point options?

Martin

-- 
Martin Hunt                     martin@cbmvax.commodore.com
Commodore-Amiga Engineering     {uunet|pyramid|rutgers}!cbmvax!martin