From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: Making --with-wide-int the default Date: Sun, 15 Nov 2015 22:36:03 +0100 Message-ID: <87h9knkksc.fsf@fencepost.gnu.org> References: <83oag087gs.fsf@gnu.org> <83oafz70im.fsf@gnu.org> <5620AF43.4050401@cs.ucla.edu> <83k2qn6xfm.fsf@gnu.org> <5620B4FA.1000804@cs.ucla.edu> <83wptojs1r.fsf@gnu.org> <56444C66.8050506@gmx.at> <83r3jugx8g.fsf@gnu.org> <87io56nu0a.fsf@fencepost.gnu.org> <83lha1dl87.fsf@gnu.org> <22087.29085.814201.779385@a1i15.kph.uni-mainz.de> <83h9knc96e.fsf@gnu.org> <22088.62318.726754.397869@a1i15.kph.uni-mainz.de> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1447704903 19970 80.91.229.3 (16 Nov 2015 20:15:03 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 16 Nov 2015 20:15:03 +0000 (UTC) Cc: rudalics@gmx.at, Eli Zaretskii , emacs-devel@gnu.org, rms@gnu.org, jwiegley@gmail.com To: Ulrich Mueller Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Nov 16 21:15:02 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZyQB1-00088V-Uq for ged-emacs-devel@m.gmane.org; Mon, 16 Nov 2015 21:15:00 +0100 Original-Received: from localhost ([::1]:48686 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZyQB1-0003hl-FA for ged-emacs-devel@m.gmane.org; Mon, 16 Nov 2015 15:14:59 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:55463) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zy5eD-0002MO-9T for emacs-devel@gnu.org; Sun, 15 Nov 2015 17:19:46 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zy5eC-0005UU-9M for emacs-devel@gnu.org; Sun, 15 Nov 2015 17:19:45 -0500 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:41378) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zy5e4-0005QT-Kh; Sun, 15 Nov 2015 17:19:36 -0500 Original-Received: from localhost ([127.0.0.1]:55194 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.82) (envelope-from ) id 1Zy5dw-0002he-L6; Sun, 15 Nov 2015 17:19:28 -0500 Original-Received: by lola (Postfix, from userid 1000) id BA947DFA96; Sun, 15 Nov 2015 22:36:03 +0100 (CET) In-Reply-To: <22088.62318.726754.397869@a1i15.kph.uni-mainz.de> (Ulrich Mueller's message of "Sun, 15 Nov 2015 22:04:46 +0100") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::e 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:194539 Archived-At: Ulrich Mueller writes: >>>>>> On Sun, 15 Nov 2015, Eli Zaretskii wrote: > >>> Date: Sat, 14 Nov 2015 18:38:37 +0100 >>> From: Ulrich Mueller >>> Cc: rudalics@gmx.at, jwiegley@gmail.com, dak@gnu.org, rms@gnu.org, >>> emacs-devel@gnu.org >>> >>> In case you want any feedback from distros, Gentoo makes the option >>> available to users as the "wide-int" use flag, and the default is off. >>> I've not seen a single complaint from users that we should change that >>> default. (So most likely the Gentoo default will stay off, regardless >>> of what you decide to do with the upstream default.) > >> Did the option you offer mention the fact that using it enlarges the >> maximum buffer and string size to (almost) 2GB? If not, it's quite >> possible that your users simply did not realize what this option would >> give them in user-level functionality, and treated it as yet another >> obscure build feature. > > This is what we have as description: > > app-editors/emacs:wide-int - Prefer wide Emacs integers (typically > 62-bit). This option has an effect only on architectures where > "long" and "long long" types have different size. > > Seems that we copied the first sentence from Emacs' configure --help > output, which also doesn't say anything about buffer size or memory > footprint. It's not really "Prefer". It makes _all_ Lisp data 64 bit (allowing for 62 bit integers instead of the usual 30 bit ones), at the obvious cost of doubling the size of Lisp cells (and immediate expressions and symbols and a few other things) to a value not natively supported by instructions and registers. > Unrelated question: Are the "62 bit" in the description above correct, > or should it rather be 61 bit? Yes. The basic type tagging is 3 bits, but two tag values are reserved for integers. So effectively only 2 bits are missing from the integer range. -- David Kastrup