X-Recipient: archive-cygwin@delorie.com X-Spam-Check-By: sourceware.org Date: Fri, 23 Dec 2011 14:52:47 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: 16 byte pthread stack alignments Message-ID: <20111223135247.GM31936@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20111221094211.GH23547@calimero.vinschen.de> <4EF1F937.9040107@gmail.com> <20111221154104.GB11841@calimero.vinschen.de> <20111221165053.GA9699@calimero.vinschen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com On Dec 22 12:51, Brian Ford wrote: > On Wed, 21 Dec 2011, Corinna Vinschen wrote: > > > On second thought I'm a bit puzzled that the pthread stack isn't > > correctly aligned as well. Ignoring the pthread_attr_setstack case > > which wasn't supported so far anyway, the OS stack set up by > > CreateThread is 64K aligned. From that 64K aligned StackBase value, I > > subtract 12704 == 0x31a0 bytes. So the result should be 16 byte > > aligned even without the andl $-16, %%esp. Why isn't it?!? > > It appears it is, here. > > > Does anybody care to tell me what's wrong with the assembler code in > > thread_wrapper? > > I don't pretend to understand why, but it appears gcc is expecting the > stack to be 16 byte aligned on entry to the called function, which > includes the 4 byte argument and the 4 byte return address in this case. > I could be wrong, but it appears that would do it. Sorry, but what I don't get from your reply is if the andl worked or not. Is the alignment correct now or do I have to move the stack down by another 8 bytes to account for the argument and the stack address? Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple