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Mail Archives: djgpp/2000/04/18/04:41:15

From: "Alexei A. Frounze" <alex DOT fru AT mtu-net DOT ru>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: THE BET
Date: Tue, 18 Apr 2000 11:28:16 +0400
Organization: MTU-Intel ISP
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Reply-To: djgpp AT delorie DOT com

Dieter Buerssner wrote:
> 
> [followup set]
> 
> Alexei A. Frounze wrote:
> 
> >I forgot about one important thing. W/o FIDIVRL executed in parallel to
> >the span() function he wouldn't get such a result. This trick is
> >unchanged by him.
> 
> This is wrong. Repeating it, doesn't make it correct.

Well, well, well.

Remember, you wrote:

-------------------8<------------------------
If you 

#define USEC 0
#define USEC2 0

you'll get your original code. With

#define USEC 1
#define USEC2 0

you'll get the code, that is actually faster
with my computer, than 
your original. I have to compile it with -O
and not -O2, to get it 
faster. All the other modules, I have let
compiled with -O2.

With

#define USEC 1
#define USEC2 1

you'll get the version with one line of inline
assembly. Again I used 
-O only
-------------------8<------------------------

Right now I'm running your source...

USEC=1,USEC2=0 makes engine as fast as original and there _is_ FIDIVRL trick
with USEC2=0. Max FPS is 70.

USEC=1,USEC2=1 makes engine slower. Max FPS is 62. And there is _no_ FIFIVRL
trick.

In both cases I used -O.

> Quick proof for the source, #defined for "Level II", without
> any of your inline assembly.
> 
> E:\test\a2>gcc -O -S tmapping.c
> 
> E:\test\a2>grep -i fidivrl tmapping.s

Finds it for the USEC=1,USEC2=0 case and doesn't find it for the USEC=1,USEC2=1
case.

> If you don't understand, RTFM.

I really don't understand. Which FM do you mean?

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


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