From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: immediate strings #2 Date: Tue, 29 Nov 2011 00:50:17 -0800 Organization: UCLA Computer Science Department Message-ID: <4ED49CC9.6080808@cs.ucla.edu> References: <4ED35057.8010103@yandex.ru> <4ED4089C.3050203@cs.ucla.edu> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1322556630 4145 80.91.229.12 (29 Nov 2011 08:50:30 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 29 Nov 2011 08:50:30 +0000 (UTC) Cc: Dmitry Antipov , emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Nov 29 09:50:25 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 1RVJOT-0004LS-5w for ged-emacs-devel@m.gmane.org; Tue, 29 Nov 2011 09:50:25 +0100 Original-Received: from localhost ([::1]:35834 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVJOS-0004Eh-Hl for ged-emacs-devel@m.gmane.org; Tue, 29 Nov 2011 03:50:24 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:55921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVJOP-0004EP-Q4 for emacs-devel@gnu.org; Tue, 29 Nov 2011 03:50:22 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RVJOL-0005uh-JV for emacs-devel@gnu.org; Tue, 29 Nov 2011 03:50:21 -0500 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:36008) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RVJOL-0005ub-B1 for emacs-devel@gnu.org; Tue, 29 Nov 2011 03:50:17 -0500 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id 36DADA60005; Tue, 29 Nov 2011 00:50:16 -0800 (PST) X-Virus-Scanned: amavisd-new at smtp.cs.ucla.edu Original-Received: from smtp.cs.ucla.edu ([127.0.0.1]) by localhost (smtp.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rO0W-Vl-WdGC; Tue, 29 Nov 2011 00:50:15 -0800 (PST) Original-Received: from [192.168.1.10] (pool-71-189-109-235.lsanca.fios.verizon.net [71.189.109.235]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id 2C82CA60001; Tue, 29 Nov 2011 00:50:15 -0800 (PST) User-Agent: Mozilla/5.0 (X11; Linux i686; rv:8.0) Gecko/20111124 Thunderbird/8.0 In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 131.179.128.62 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:146342 Archived-At: On 11/28/11 18:07, Stefan Monnier wrote: > There are bits available in size and size_byte, we > have to use those (like we currently do with gcmarkbit in `size') There is a bit available in size (since it's always nonnegative) but not in size_byte (since it ranges from -1 .. PTRDIFF_MAX and is a ptrdiff_t, assuming a 32-bit host configured --with-wide-int and assuming the memory-saving patch of Bug#9874). This is in contrast with our current uses of mark bits (e.g., ARRAY_MARK_FLAG), which use bits that are otherwise unused, even if a vector has its maximal size. We can fairly easily get that bit back from size_byte by restricting its range to (say) 0 .. PTRDIFF_MAX. So this is a fairly minor glitch that can be fixed but is not yet fixed in the current proposal.