Message-Id: <m0zGjnM-000S4TC@inti.gov.ar>
Comments: Authenticated sender is <salvador AT natacha DOT inti DOT gov DOT ar>
From: "Salvador Eduardo Tropea (SET)" <salvador AT inti DOT gov DOT ar>
Organization: INTI
To: Endlisnis <s257m AT unb DOT ca>, djgpp AT delorie DOT com
Date: Wed, 9 Sep 1998 09:59:09 +0000
MIME-Version: 1.0
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7BIT
Subject: Re: Bug in GCC?
In-reply-to: <35F5B07A.8E37D184@unb.ca>
Precedence: bulk

Endlisnis <s257m AT unb DOT ca> wrote:

> Eli Zaretskii wrote:
> > 
> > On Mon, 7 Sep 1998, Endlisnis wrote:
> > 
> > > > * Post the complete asm produced.
> > >       I don't know how to do that.
> > 
> > Add -S to the compilation switches.
> 
> OK, Here is the input file, which seems to compile differently when giving asm
> output, but it still isn't right!  And included is the complete asm output, I
> marked the place where it screws up, in the add function.  Is there something
> I'm doing wrong?
> 
> #include <iostream.h>
> 
> int add(int a, int b)
> {
>  int Ret;
>  asm ("addl %1, %0"  //this line compiles to "addl ecx,ecx".
>  : "=&r" (Ret)
>  : "0" (a), "r" (b)
>  );
>  return Ret;
>  }
 
I guess that's just an example, no? There is no need for such a routine. 
Anyways ... it doesn't look right try it:

int add(int a,int b)
{
 int ret;
 asm ("movl %2,%0; addl %1,%0" : "rm="(ret) : "r"(b), "r"(a));
 return ret;
}

Compiled with -O2 gives

 .file	"p.c"
gcc2_compiled.:
___gnu_compiled_c:
.text
 .p2align 2
.globl _add
_add:
 pushl %ebp
 movl %esp,%ebp
 movl 12(%ebp),%edx
 movl 8(%ebp),%ecx
/APP
 movl %ecx,%eax; addl %edx,%eax
/NO_APP
 leave
 ret

But again isn't a good idea a rotine to make just a simple add because gcc 
will do it pretty well alone.

SET
------------------------------------ 0 --------------------------------
Visit my home page: http://set-soft.home.ml.org/
or
http://www.geocities.com/SiliconValley/Vista/6552/
Salvador Eduardo Tropea (SET). (Electronics Engineer)
Alternative e-mail: set-soft AT usa DOT net set AT computer DOT org
ICQ: 2951574
Address: Curapaligue 2124, Caseros, 3 de Febrero
Buenos Aires, (1678), ARGENTINA
TE: +(541) 759 0013