From:	Endlisnis <s257m AT unb DOT ca>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Not a bug in GCC. Was: Bug in GCC?
Date:	Thu, 10 Sep 1998 20:47:25 -0300
Organization:	NBTel Internet
Lines:	25
Message-ID:	<35F8650D.D00F5779@unb.ca>
References:	<m0zHArk-000S5AC AT inti DOT gov DOT ar>
NNTP-Posting-Host:	fctnts13c40.nbnet.nb.ca
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Salvador Eduardo Tropea (SET) wrote:
> > > int add(int a,int b)
> > > {
> > >  int ret;
> > >  asm ("movl %2,%0; addl %1,%0" : "rm="(ret) : "r"(b), "r"(a));
> > >  return ret;
> > > }
> >       But, your requires an extra move!  I actually found the problem in my code,
> > not the compiler.
> The move is needed, i386 chips doesn't support add mem,mem so you must move
> to a register, explicitly or not (in the last case gcc does the move).
	No, you are moving from %2 (must be a register "r") to %0 (could be memory
"rm="), which doesn make sence.  It actually compiles to 
movl %ecx, %eax  //useless code.
addl %ebc, %eax

> Good, but again: I hope that's just an example, you won't really use it, no?
	I was actually trying to teach someone asm, but the code didn't compile as I
expected.
-- 
     (\/) Endlisnis (\/)
          s257m AT unb DOT ca
          Endlisnis AT GeoCities DOT com
          Endlis AT nbnet DOT nb DOT ca

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