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: Mon, 28 Nov 2011 14:18:04 -0800 Organization: UCLA Computer Science Department Message-ID: <4ED4089C.3050203@cs.ucla.edu> References: <4ED35057.8010103@yandex.ru> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1322518704 6079 80.91.229.12 (28 Nov 2011 22:18:24 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 28 Nov 2011 22:18:24 +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 Mon Nov 28 23:18:20 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 1RV9Wm-0006k8-6s for ged-emacs-devel@m.gmane.org; Mon, 28 Nov 2011 23:18:20 +0100 Original-Received: from localhost ([::1]:51426 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RV9Wl-0002Vs-Od for ged-emacs-devel@m.gmane.org; Mon, 28 Nov 2011 17:18:19 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:46655) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RV9Wi-0002Te-4X for emacs-devel@gnu.org; Mon, 28 Nov 2011 17:18:18 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RV9Wf-0005Pi-FY for emacs-devel@gnu.org; Mon, 28 Nov 2011 17:18:16 -0500 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:57892) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RV9Wf-0005NX-3z for emacs-devel@gnu.org; Mon, 28 Nov 2011 17:18:13 -0500 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id C8512A60003; Mon, 28 Nov 2011 14:18:04 -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 exiLStkaX5Wa; Mon, 28 Nov 2011 14:18:04 -0800 (PST) Original-Received: from penguin.cs.ucla.edu (Penguin.CS.UCLA.EDU [131.179.64.200]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id 51748A60001; Mon, 28 Nov 2011 14:18:04 -0800 (PST) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 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:146325 Archived-At: On 11/28/11 09:33, Stefan Monnier wrote: > You need to move the immbit and gcmarkbit > into the union :-( Yes, something like this perhaps? It also adds a bit of checking for underlying assumptions about word size. #include #define IMMEDIATE_STRING_LENGTH_BITS 7 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; }; #define IMMEDIATE_STRING_SIZE \ (sizeof (struct Data_Lisp_String) - offsetof (struct Data_Lisp_String, size)) verify (IMMEDIATE_STRING_SIZE <= 1 << (IMMEDIATE_STRING_LENGTH_BITS - 1)); struct Immediate_Lisp_String { unsigned int immediate_bit : 1; signed int size : IMMEDIATE_STRING_LENGTH_BITS; unsigned int gcmarkbit : 1; signed int size_byte : IMMEDIATE_STRING_LENGTH_BITS; INTERVAL intervals; unsigned char data[IMMEDIATE_STRING_SIZE]; }; union Lisp_String { /* When IMMEDIATE.IMMEDIATE_BIT is 0. */ struct Data_Lisp_String data; /* When IMMEDIATE.IMMEDIATE_BIT is 1. */ struct Immediate_Lisp_String immediate; };