Message-ID: <37E35D92.666CBF7E@pmail.net>
Date: Sat, 18 Sep 1999 11:38:26 +0200
From: Fred Backman <fredrick DOT backman AT pmail DOT net>
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To: djgpp AT delorie DOT com
Subject: optimizing vs packing .EXE (Re: e: Why the executables r so big ????)
References: <c_LD3.2608$_3 DOT 44552 AT news DOT tpnet DOT pl> <37E01676 DOT D74EEBDC AT pmail DOT net> <02e54bec DOT 79e180d5 AT usw-ex0102-016 DOT remarq DOT com>
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Reply-To: djgpp AT delorie DOT com

I agree as far as packing an .EXE goes. I don't know how UPX works, but I have a
feeling it is no more than a packing tool, e.g. it does not modify any code but
"only" removes redundant information and packs everything else. For instance,
isn't it true that an executable usually have some unused areas because the
different segments cannot start right after one another but have to begin at the
next paragraph boundary, and this can mean a lot of unused space which in turn
means bigger .exe?

On the other hand, I'm pretty sure it's possible to make a tool which actually
optimizes/packs the .exe in the sense that it modifies the code and makes it run
faster (e.g. less instructions or cycles), however I don't think there is such a
tool which works on .EXE files...is there?

Varence wrote:

>   Packers like UPX don't improve your binary's performance
> in any way.  They pack the binary (as the name suggests) so
> it's compressed.  It doesn't do any optimization on the
> code or change how the routines are used within it.
>     So essentially, not only does packing a binary not
> improve it's performance, it actually adds a small overhead
> at initialization for the unpacking process.
>
> In article <37E01676 DOT D74EEBDC AT pmail DOT net>, Fredrick Backman
> <fredrick DOT backman AT pmail DOT net> wrote:
> > Keep in mind though that the difference in
> > _performance_ may not improve
> > very much if you make the .exe file smaller, IMHO the
> > main reason to go
> > through this is (a) to make the download .ZIP file
> > smaller and (b) it's
> > cool to have a 235kb exe rather than 700.
> > Cheers
> > Fred
> > --
> > Fred Backman
> > Lead Wizard
> > Binary Spells
> > www.binaryspells.com
>
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