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Mail Archives: djgpp/2000/04/19/15:00:24

From: "Alexei A. Frounze" <alex DOT fru AT mtu-net DOT ru>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: inefficiency of GCC output code & -O problem
Date: Wed, 19 Apr 2000 19:57:48 +0400
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Eli Zaretskii wrote:
> 
> On Tue, 18 Apr 2000, Alexei A. Frounze wrote:
> 
> > Cyrix 6x86.
> > Originally it was P266, but something burnt out and now it doesn't work on
> > frequencies higher than 133MHz anymore. IMHO a good CPU
> 
> It's not a question of ``good'' or ``bad''.  Cyrix is different from
> K6.  In particular, K6 is known to write to memory very fast, but read
> much slower (or the other way around, I don't remember).  It's also
> much more sensitive to alignment of data and code.

I simply told that in order to mention that it's not a Ciryx 6x86 P266 and Cyrix
P133. It's something new now. :)

> Since you asked what might be the cause of different behavior of the
> same code, I was suggesting that one of the differences between
> processors is the reason for the different effects of changes in code
> on performance.

So then the division trick is better for most of the CPUs, since the inline ASM
with this division doesn't make the code noticable slow. It makes it faster. My
computer/CPU is the example.

bye.
Alexei A. Frounze
-----------------------------------------
Homepage: http://alexfru.chat.ru
Mirror:   http://members.xoom.com/alexfru


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