From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/3875 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: Conformance issues to address after 0.9.12 release Date: Tue, 13 Aug 2013 00:25:02 -0400 Message-ID: <20130813042502.GC221@brightrain.aerifal.cx> References: <20130729063456.GA31564@brightrain.aerifal.cx> <20130729160046.GC25714@port70.net> <20130729210448.GG4284@brightrain.aerifal.cx> <20130730022621.GF25714@port70.net> <20130812192704.GE5368@port70.net> <20130813033231.GB221@brightrain.aerifal.cx> <20130813034555.GF5368@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1376367913 18742 80.91.229.3 (13 Aug 2013 04:25:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 13 Aug 2013 04:25:13 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-3879-gllmg-musl=m.gmane.org@lists.openwall.com Tue Aug 13 06:25:16 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1V96AV-0000DG-DF for gllmg-musl@plane.gmane.org; Tue, 13 Aug 2013 06:25:15 +0200 Original-Received: (qmail 12099 invoked by uid 550); 13 Aug 2013 04:25:14 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 12091 invoked from network); 13 Aug 2013 04:25:14 -0000 Content-Disposition: inline In-Reply-To: <20130813034555.GF5368@port70.net> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:3875 Archived-At: On Tue, Aug 13, 2013 at 05:45:55AM +0200, Szabolcs Nagy wrote: > * Rich Felker [2013-08-12 23:32:32 -0400]: > > Why the push/pop? Is there a reason you can't just store over top of > > the argument slot at 4(%esp) or even below the stack pointer at > > -4(%esp)? The latter would be unsafe if you ever wanted to read back > > the value since it could be clobbered asynchronously by a signal > > handler, but you don't want/need to read it back anyway. > > ah ok > did not know the callee can modify those Yes, the argument zone on the stack belongs to the callee. This is what makes tail calls possible; otherwise the only functions you could tail-call to would be ones that take no arguments. (Of course you can only tail-call to a function that takes the same or less space for its arguments.) Rich