From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: immediate strings #2 Date: Mon, 28 Nov 2011 21:07:35 -0500 Message-ID: References: <4ED35057.8010103@yandex.ru> <4ED4089C.3050203@cs.ucla.edu> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1322532476 28787 80.91.229.12 (29 Nov 2011 02:07:56 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 29 Nov 2011 02:07:56 +0000 (UTC) Cc: Dmitry Antipov , emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Nov 29 03:07:47 2011 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RVD6n-0001rr-Tt for ged-emacs-devel@m.gmane.org; Tue, 29 Nov 2011 03:07:46 +0100 Original-Received: from localhost ([::1]:33691 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVD6m-0005QN-Kb for ged-emacs-devel@m.gmane.org; Mon, 28 Nov 2011 21:07:44 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:59092) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVD6j-0005Q5-RC for emacs-devel@gnu.org; Mon, 28 Nov 2011 21:07:42 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RVD6i-0002JG-U9 for emacs-devel@gnu.org; Mon, 28 Nov 2011 21:07:41 -0500 Original-Received: from chene.dit.umontreal.ca ([132.204.246.20]:44141) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVD6i-0002Iu-Qk for emacs-devel@gnu.org; Mon, 28 Nov 2011 21:07:40 -0500 Original-Received: from pastel.home (lechon.iro.umontreal.ca [132.204.27.242]) by chene.dit.umontreal.ca (8.14.1/8.14.1) with ESMTP id pAT27Zwr020746; Mon, 28 Nov 2011 21:07:36 -0500 Original-Received: by pastel.home (Postfix, from userid 20848) id 8EBD558BB2; Mon, 28 Nov 2011 21:07:35 -0500 (EST) In-Reply-To: <4ED4089C.3050203@cs.ucla.edu> (Paul Eggert's message of "Mon, 28 Nov 2011 14:18:04 -0800") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.91 (gnu/linux) X-NAI-Spam-Flag: NO X-NAI-Spam-Threshold: 5 X-NAI-Spam-Score: 0 X-NAI-Spam-Rules: 1 Rules triggered RV4055=0 X-NAI-Spam-Version: 2.2.0.9286 : core <4055> : streams <706097> : uri <1017924> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 132.204.246.20 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:146331 Archived-At: > struct Data_Lisp_String > { > unsigned int immediate_bit : 1; > signed int : IMMEDIATE_STRING_LENGTH_BITS; /* padding for immediate size */ > unsigned int gcmarkbit : 1; > signed int : IMMEDIATE_STRING_LENGTH_BITS; /* and for immediate size_byte */ > INTERVAL intervals; > ptrdiff_t size; > ptrdiff_t size_byte; > unsigned char *data; > }; Why? IIUC that sums up to 5x32bit, which will break the "multiple of 8 alignment" rule and hence will need to be be rounded up to 6x32bit, for an overall increase of 50% in the size of struct Lisp_String. I.e. a non-starter. There are bits available in size and size_byte, we have to use those (like we currently do with gcmarkbit in `size'). Stefan