Path: utzoo!utgpu!watserv1!watmath!ria!uwovax!7103_2622
From: 7103_2622@uwovax.uwo.ca (Eric Smith)
Newsgroups: comp.sys.atari.st
Subject: Re: GNU C Floating Point Math
Message-ID: <4470.257da18c@uwovax.uwo.ca>
Date: 7 Dec 89 04:32:28 GMT
References: <3497@jhunix.HCF.JHU.EDU> <1989Dec4.210245.2798@usenet.ins.cwru.edu> <3526@jhunix.HCF.JHU.EDU>
Lines: 30

In article <3526@jhunix.HCF.JHU.EDU>, esp_05@jhunix.HCF.JHU.EDU (Stdnt 05) writes:
> I just downloaded the copy of GNU C from terminator, oh, two weeks
> ago, the same time I downloaded the pml package.  Maybe I should try
> drgsun.
> 
Yes, dsrgsun has slightly more up to date versions.

> At any rate Megamax C blew GNU C away in speed and executable size
> (GNU C took twice as long, and the executables were around twice as
> large).  The only problem with it is that it doesn't have stdlib
> functions, although without those I can still improvise.
GNU C executables are twice as large only for small files (the library is
more complicated, and not as well organized, so it has higher overhead).
For larger files I would expect the GCC to produce smaller code. And yes,
GNU takes longer to compile; Laser is *really* fast. On the other hand,
programs compiled with GNU execute faster, and the GNU optimizer is a *lot*
smarter than Megamax's (GNU knows not only when to put things in registers,
but also how to change multiplications into additions inside of loops,
so that "for (i = 0; i < end; i++) a[i]=foo(i);" produces the same code
as "for (p = a; p < a[end]; ++p) *p++ = foo(p-a);".

One other note: the library as distributed has a serious bug in the compare
routine for floats. That should be fixed soon; a temporary workaround is
to use doubles instead of floats. This may have been causing your problems.
--
Eric R. Smith                     email:
Dept. of Mathematics            ERSMITH@uwovax.uwo.ca
University of Western Ontario   ERSMITH@uwovax.bitnet
London, Ont. Canada N6A 5B7
ph: (519) 661-3638