lkml.org 
[lkml]   [2001]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Compilation problem in ndisc.c / 2.5.1-pre2 : possible gcc bug?
"Richard B. Johnson" wrote:
>
> On Wed, 28 Nov 2001, Martin Eriksson wrote:
>
> > ----- Original Message -----
> > From: "Richard B. Johnson" <root@chaos.analogic.com>
> > To: <erik@hensema.net>
> > Cc: <linux-kernel@vger.kernel.org>
> > Sent: Wednesday, November 28, 2001 8:09 PM
> > Subject: Re: Compilation problem in ndisc.c / 2.5.1-pre2 : possible gcc bug?
> >
> >
> > > On 28 Nov 2001, Erik Hensema wrote:
> > >
> > > >
> > > > I've been looking into the compile problems of net/ipv6/ndisc.c in
> > > > 2.5.1-pre2 and I found that the asm generated by gcc (2.95.3) is wrong:
> > > >
> > > > This is a small part of a diff betweem two asm files generated by gcc,
> > note
> > > > the missing \n's in the wrong code:
> > > >
> > > > -
> > > > - addl 0(%ebp), %edx
> > > > - adcl 4(%ebp), %edx
> > > > - adcl 8(%ebp), %edx
> > > > - adcl 12(%ebp), %edx
> > > > - adcl 0(%ecx), %edx
> > > > - adcl 4(%ecx), %edx
> > > > - adcl 8(%ecx), %edx
> > > > - adcl 12(%ecx), %edx
> > > > - adcl %edi, %edx
> > > > - adcl %eax, %edx
> > > > - adcl $0, %edx
> > > > -
> > > > + addl 0(%ebp), %edxadcl 4(%ebp), %edxadcl 8(%ebp), %edxadcl 12(%ebp),
> > %edxadcl 0(%ecx), %edxadcl 4(%ecx), %edxadcl 8(%ecx), %edxadcl 12(%ecx),
> > %edxadcl %edi, %edxadcl %eax, %edxadcl $0, %edx
> > >
> > >
> > > This is probably just some loop unrolling, not some as you say "wrong
> > > code".
> >
> > Correct me if I'm wrong, but I don't think "%edxadcl" really assembles....
>
> No, but an edited 'diff' of the assembly output of a 'C' compiler doesn't
> really tell much. Note, no line numbers, no clue as to what the diff
> was about. The actual defective section of code would be much more
> instructive. For instance, is this as a result of an in-line macro
> expansion; the result of a <CR><LF> 'dos' file; the true output of
> a 'C' file with no __inline__ __asm__?

It's from include/asm-i386/checksum.h, specifically csum_ipv6_magic().
The asm statements in this header file need semicolons or explicit
newlines after each opcode.

--

Brian Gerst
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:13    [W:0.099 / U:7.340 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site