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From: jsm@phoenix.Princeton.EDU (John Scott McCauley Jr.)
Newsgroups: comp.sys.atari.st
Subject: Re: Comment on PD/Shareware C compiler (realy GCC stinks?)
Message-ID: <8209@phoenix.Princeton.EDU>
Date: 8 May 89 01:51:41 GMT
References: <1048@orbit.UUCP> <1471@atari.UUCP> <703@forty2.UUCP> <539@TSfR.UUCP>
Reply-To: jsm@phoenix.Princeton.EDU (John Scott McCauley Jr.)
Organization: Princeton University, NJ
Lines: 35

Just to add my $0.02 about GCC on the Atari ST. Last summer I was
doing cross-compiles. The numbers here are approximately right --
they are from memory.  I was getting 750+ Drystones a sec (after
optimal tweaking) on my monochrome 1040 ST.  The same code (except
for i/o routines) was running about six times faster on a 20 Mhz Sun 3
with a 68020. This was about 20% better than the Sun C compiler.
(Both Sun and GNU have come out with faster versions since then.)

There are three factors (at least) to take into account:

1) Memory bandwidth. The 020 can do 32 bit fetches where the 000  
   has to fetch 16 bits at once.
2) Clock speed. Asuming 100% cache hits, we should see 25 Mhz out of
   the Sun.
3) The 020 has better timings on some 000 instructions I think. I
   tried both 000 and 020 code on the Sun, and there was little 
   difference.

If you assume that the 1) and 2) are the main factors, then I was getting
the Atari ST dps figure within 10% (factor of 3 for clock speed, factor
of 2 for memory access).

So perhaps I should run small model Atari ST code on the Sun and get
10,000+ dps.... Wow! Instant Vax 8700!

		Scott




-- 
Scott McCauley, jsm@phoenix.princeton.edu (INTERNET)
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