From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: 16 byte pthread stack alignments
Date: Mon, 09 Jan 2012 17:36:00 -0000 [thread overview]
Message-ID: <20120109173605.GA25130@calimero.vinschen.de> (raw)
In-Reply-To: <Pine.CYG.4.58.1201090937510.2448@PC1163-8460-XP.flightsafety.com>
On Jan 9 09:41, Brian Ford wrote:
> On Mon, 9 Jan 2012, Corinna Vinschen wrote:
>
> > On Dec 27 18:06, Brian Ford wrote:
> > > On Fri, 23 Dec 2011, Corinna Vinschen wrote:
> > >
> > > > Sorry, but what I don't get from your reply is if the andl worked or
> > > > not.
> > >
> > > No; by itself, it does not. Adding a "subl $12, %%esp" following it so
> > > that the stack is 16 byte aligned after the thread arg is pushed does
> > > work. There are probably more efficient and/or cleaner ways of doing it
> > > though.
> > >
> > > STC attached, but note that it seems to always pass with gcc-4. Only gcc
> > > 3.4.4 appears to require the extra alignment.
> >
> > Ok, this is even more puzzeling. The thread function called from the
> > thread_wrapper function is NOT the application thread function, but the
> > Cygwin internal function thread_init_wrapper. Given that this function
> > is built with the same gcc 4.x compiler as the rest of Cygwin, how on
> > earth can this fail at all? Shouldn't the alignment be always correct on
> > the subsequent call to the application function, given that gcc-4 is
> > supposed to care?
>
> I'm speculating, but I believe gcc-4 only re-aligns the stack in case an
> instruction in that function requires more strict alignment than the
> default ABI to save overhead.
Maybe. I applied that patch which also makes gcc 3 happy.
Corinna
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Corinna Vinschen Please, send mails regarding Cygwin to
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next prev parent reply other threads:[~2012-01-09 17:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-20 23:45 Brian Ford
2011-12-21 9:42 ` Corinna Vinschen
2011-12-21 10:46 ` Corinna Vinschen
2011-12-21 15:20 ` Dave Korn
2011-12-21 15:41 ` Corinna Vinschen
2011-12-21 16:22 ` Brian Ford
2011-12-21 16:51 ` Corinna Vinschen
2011-12-22 18:51 ` Brian Ford
2011-12-23 13:53 ` Corinna Vinschen
2011-12-28 0:12 ` Brian Ford
2012-01-09 14:14 ` Corinna Vinschen
2012-01-09 15:41 ` Brian Ford
2012-01-09 17:36 ` Corinna Vinschen [this message]
2011-12-21 18:20 ` Brian Ford
2011-12-21 21:25 ` Brian Ford
2011-12-22 9:28 ` Corinna Vinschen
2011-12-22 15:20 ` Brian Ford
2011-12-22 15:32 ` Corinna Vinschen
2011-12-22 15:40 ` Corinna Vinschen
2011-12-22 15:50 ` Brian Ford
2011-12-22 15:48 ` Brian Ford
2011-12-21 16:13 ` Brian Ford
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