From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761050AbXEQXgB (ORCPT ); Thu, 17 May 2007 19:36:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756688AbXEQXfy (ORCPT ); Thu, 17 May 2007 19:35:54 -0400 Received: from terminus.zytor.com ([192.83.249.54]:49324 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756547AbXEQXfx (ORCPT ); Thu, 17 May 2007 19:35:53 -0400 Message-ID: <464CE6B2.5090403@zytor.com> Date: Thu, 17 May 2007 16:35:14 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Linux Torvalds , Linux Kernel Mailing List Subject: Re: [PATCH] Further update of the i386 boot documentation References: <200705172250.l4HMol8f004870@tazenda.hos.anvin.org> <464CE105.7030808@goop.org> <464CE38B.8010802@zytor.com> <464CE5A4.3040106@goop.org> In-Reply-To: <464CE5A4.3040106@goop.org> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > H. Peter Anvin wrote: >> Given that we have already established littleendian byte order, it's the >> same thing. >> > > Well, not quite; mentioning the string form first creates an ambiguity. > I'd express as something like: ``The magic number is 0x53726448 > (implicitly, stored little-endian), which breaks down to the characters > "HdrS".'' It does not create any ambiguity whatsoever. The two are equivalent forms, and either is authoritative. >>>> + >>>> +Field name: version >>>> +Type: read >>>> +Offset/size: 0x206/2 >>>> +Protocol: 2.00+ >>>> + >>>> + Contains the boot protocol version, e.g. 0x0204 for version 2.04. >>>> >>>> >>> So the version is in BCD? >>> >> Valid objection. It probably should be considered as (major, minor) >> bytes, but we haven't had any releases where it hasn't also been valid >> BCD. I would prefer separate bytes myself, so 2.10 = 0x20a instead of >> 2.10 = 0x210. > > OK. So is the major or minor at the lower address? Minor. Littleendian. > 0x00 or \0-terminated is idiomatic and unambigous. Not a big deal > either way. Null-terminated is idiomatic and unambiguous. -hpa