From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Pip Cet Newsgroups: gmane.emacs.devel Subject: Re: MPS: weak hash tables Date: Sat, 06 Jul 2024 06:31:14 +0000 Message-ID: References: <_mNcR6ailVKpYHLxgfo_tJlYGeR0AQIzQWluspYYp5_g5pIIKkHLNfFkklQQgOKNiVW8jn8NS3i2dJ7_B2Qyx9v-Dq3MQ9mP8HNL30UWsqY=@protonmail.com> <864j946kbe.fsf@gnu.org> <3hUiHuwpNB-2QtvUKSxx3e3-ZUX_xSI4WMW-BDSuybaKMQ3WTjpI2oVBe4Xato-h8bE-d24VQq9I8tE4x-G1-wyKuBD8cGkwaFggC91ndNM=@protonmail.com> <86wmlz59uk.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="6307"; mail-complaints-to="usenet@ciao.gmane.io" Cc: gerd.moellmann@gmail.com, eller.helmut@gmail.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Jul 06 08:49:27 2024 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sPzEc-0001Oh-PZ for ged-emacs-devel@m.gmane-mx.org; Sat, 06 Jul 2024 08:49:26 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sPzEC-0002Zj-Rs; Sat, 06 Jul 2024 02:49:00 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sPyx9-0006BM-6J for emacs-devel@gnu.org; Sat, 06 Jul 2024 02:31:23 -0400 Original-Received: from mail-4322.protonmail.ch ([185.70.43.22]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sPyx6-0005R1-I1; Sat, 06 Jul 2024 02:31:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1720247477; x=1720506677; bh=+btgf4wIV/UtkLFvorDTBtrazN4pZA44l8Ov9jih0kE=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=v3X7P2cpoAGwbDg9s2L4HGgZbGuC48qL3DA+0RANzktiPQNB4NfubH/MBykG1roqS lUVmJDrvJo99Z4fAJyzqmqSC50qMhVItd69bAV6c/Dj6XXeoZ6iL0HZ/mYXvoq3W66 ePVO2RnJaiBf769+GNi4JKyE5ezsHrkYd/8CX7rTeLNF5n1Uibl2ESnvxhqBpY9woL NUFSLDRGIclg02DgBauRvfhdVqnywpMGlc9YP+sBD0AJQQoTUhazJHdrY/12jkOd22 Np1w5wzNlF1RLn4MmfzOi+1HPEmfKajvbE1PcWeFkrc/7FqshDcZ+mZKkbQOrwy/c2 aP3RR/MCPPyXw== In-Reply-To: <86wmlz59uk.fsf@gnu.org> Feedback-ID: 112775352:user:proton X-Pm-Message-ID: b7a6300d99b4ce97d836be533164bf7fecfb5b49 Received-SPF: pass client-ip=185.70.43.22; envelope-from=pipcet@protonmail.com; helo=mail-4322.protonmail.ch X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Sat, 06 Jul 2024 02:48:57 -0400 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:321411 Archived-At: On Saturday, July 6th, 2024 at 06:10, Eli Zaretskii wrote: > > Date: Fri, 05 Jul 2024 20:35:34 +0000 >=20 > > From: Pip Cet pipcet@protonmail.com > > Cc: gerd.moellmann@gmail.com, eller.helmut@gmail.com, emacs-devel@gnu.o= rg > >=20 > > > > At least we've excluded WIDE_EMACS_INT :-) > > > > Which is a pity, IMNSHO, and a major disappointment for me personal= ly, > > > > since I'm a happy user of that configuration for many years. > >=20 > > Interesting. It's not too hard to fit a 62-bit integer into two 32-bit = integers which are not 4-bit aligned, of course. I'm not sure what else wou= ld go wrong though :-) >=20 > The problem, AFAIU, is the MPS assumption that Lisp objects can fit > into a "word", which in their parlance means integral data type whose > width is the same as a pointer's. And that is false in WIDE_EMACS_INT > builds, because Lisp objects are 64-bit wide, whereas pointers are > still 32-bit. I may be misunderstanding something. When talking about normal (strong) obj= ects, MPS assumes very little about how the actual objects are represented,= as long as they can be turned into references for tracing. I don't think t= hat's going to be a problem. When dealing with weak options, the IA-32 prob= lem does mean that pointers need to be aligned and non-pointers need to be = non-aligned or 0, so we'd need to mangle big fixnums before storing them in= what, to MPS, is two 32-bit words. Pip