From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Richard Stallman Newsgroups: gmane.emacs.devel Subject: Re: start_of_data and RISCOS Date: Mon, 22 Jul 2002 09:19:15 -0600 (MDT) Sender: emacs-devel-admin@gnu.org Message-ID: <200207221519.g6MFJF002235@aztec.santafe.edu> References: Reply-To: rms@gnu.org NNTP-Posting-Host: localhost.gmane.org X-Trace: main.gmane.org 1027351238 21586 127.0.0.1 (22 Jul 2002 15:20:38 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Mon, 22 Jul 2002 15:20:38 +0000 (UTC) Cc: emacs-devel@gnu.org Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by main.gmane.org with esmtp (Exim 3.33 #1 (Debian)) id 17WezF-0005c3-00 for ; Mon, 22 Jul 2002 17:20:37 +0200 Original-Received: from fencepost.gnu.org ([199.232.76.164]) by quimby.gnus.org with esmtp (Exim 3.12 #1 (Debian)) id 17WfD8-0007eX-00 for ; Mon, 22 Jul 2002 17:34:58 +0200 Original-Received: from localhost ([127.0.0.1] helo=fencepost.gnu.org) by fencepost.gnu.org with esmtp (Exim 3.35 #1 (Debian)) id 17Wez8-0004EV-00; Mon, 22 Jul 2002 11:20:30 -0400 Original-Received: from pele.santafe.edu ([192.12.12.119]) by fencepost.gnu.org with esmtp (Exim 3.35 #1 (Debian)) id 17Wexx-00046A-00; Mon, 22 Jul 2002 11:19:17 -0400 Original-Received: from aztec.santafe.edu (aztec [192.12.12.49]) by pele.santafe.edu (8.11.6+Sun/8.11.6) with ESMTP id g6MFJMB05091; Mon, 22 Jul 2002 09:19:22 -0600 (MDT) Original-Received: (from rms@localhost) by aztec.santafe.edu (8.10.2+Sun/8.9.3) id g6MFJF002235; Mon, 22 Jul 2002 09:19:15 -0600 (MDT) X-Authentication-Warning: aztec.santafe.edu: rms set sender to rms@aztec using -f Original-To: raeburn@raeburn.org In-Reply-To: (message from Ken Raeburn on Sun, 21 Jul 2002 15:31:51 -0400) Errors-To: emacs-devel-admin@gnu.org X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.0.11 Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: Emacs development discussions. List-Unsubscribe: , List-Archive: Xref: main.gmane.org gmane.emacs.devel:5964 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:5964 Currently the preference order for defining start_of_data is to use the address of "etext" if BSD_SYSTEM is defined and DATA_SEG_BITS is not, regardless of whether DATA_START is defined. Since defining DATA_SEG_BITS also turns on the inclusive-or every time a Lisp_Object handle is turned into a pointer, I'd like to reverse that -- use DATA_START for start_of_data if it's defined, otherwise consider doing the etext bit. Using DATA_START first is ok provided you check all the platforms on which DATA_START is defined and verify this won't break them. You have started doing that: I've done some poking around at the config files, and it looks like MIPS running RISCOS 4 or 5 in BSD mode is the interesting case. But under RISCOS, it may be the case that DATA_START and BSD_SYSTEM are defined and DATA_SEG_BITS is not, so that it might be using "&etext" for start_of_data even though DATA_START is 0x800000. The next question is, does it actually make a difference if start_of_data returns DATA_START instead of &etext? Let's look at the places that use start_of_data and see if this would matter. start_of_data is used mainly in some unex*.c files, and unexmips.c does not use it. vm-limit.c is the only other use, and I think it will be better off with a closer value of start_of_data. So I conclude that your change is safe.