From: mdruiter AT cs DOT vu DOT nl (Ruiter de M)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Question about optimization of DJGPP
Date: 22 Apr 1998 12:36:24 GMT
Organization: Fac. Wiskunde & Informatica, VU, Amsterdam
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Message-ID: <6hko88$bea$1@star.cs.vu.nl>
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To: djgpp AT delorie DOT com
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> > I've made a little program and when I looked in the disassembler
> > window while running the program, I saw movl %eax,%eax. Why is
> > this instruction there? Did I forget to turn on optimization
> > somewhere?

Be sure to use -O or -O2 on the command-line. But I don't think
that's the problem. Could be because the compiler tries to align
jump-labels at 4 (or 8) byte boundaries for speed. Maybe the movl
%eax,%eax is faster than two nop's?

> Uhm.. It's because the compiler is like stupid and stuff..

No it's not. GCC is (at least one of) the best optimizing portable
compiler around.

-- 
Groeten, Michel.        http://www.cs.vu.nl/~mdruiter
  ____________
  \  /====\  /          "You know, Beavis, you need things that suck,
   \/      \/           to have things that are cool", Butt-Head.