From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1JCOFO-0007MS-0p for mharc-grub-devel@gnu.org; Tue, 08 Jan 2008 18:52:42 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JCOFM-0007Kf-AJ for grub-devel@gnu.org; Tue, 08 Jan 2008 18:52:40 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JCOFK-0007IY-P7 for grub-devel@gnu.org; Tue, 08 Jan 2008 18:52:39 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JCOFK-0007IH-Jl for grub-devel@gnu.org; Tue, 08 Jan 2008 18:52:38 -0500 Received: from c60.cesmail.net ([216.154.195.49]) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.60) (envelope-from ) id 1JCOFK-0000Kq-9x for grub-devel@gnu.org; Tue, 08 Jan 2008 18:52:38 -0500 Received: from unknown (HELO relay.cesmail.net) ([192.168.1.81]) by c60.cesmail.net with ESMTP; 08 Jan 2008 18:52:37 -0500 Received: from [192.168.1.21] (static-72-92-88-10.phlapa.fios.verizon.net [72.92.88.10]) by relay.cesmail.net (Postfix) with ESMTP id 0F951618FE1 for ; Tue, 8 Jan 2008 18:52:37 -0500 (EST) From: Pavel Roskin To: The development of GRUB 2 In-Reply-To: <20080108233718.GB10662@thorin> References: <20080108105057.GA24604@thorin> <1199816665.30874.13.camel@dv> <20080108202455.GA22878@thorin> <1199833036.21357.12.camel@dv> <20080108233718.GB10662@thorin> Content-Type: text/plain Date: Tue, 08 Jan 2008 18:52:36 -0500 Message-Id: <1199836356.21357.23.camel@dv> Mime-Version: 1.0 X-Mailer: Evolution 2.12.2 (2.12.2-2.fc8) Content-Transfer-Encoding: 7bit X-detected-kernel: by monty-python.gnu.org: Genre and OS details not recognized. Subject: Re: contradiction in boot/i386/pc/boot.S X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jan 2008 23:52:40 -0000 On Wed, 2008-01-09 at 00:37 +0100, Robert Millan wrote: > On Tue, Jan 08, 2008 at 05:57:16PM -0500, Pavel Roskin wrote: > > > > We can save 4 more bytes if we do "orb $0x80, %dl" unconditionally for > > the hard drives. However, I'm not sure if there are BIOSes that pass 1 > > in %dl and how critical it would be if it becomes 0x81. > > I think the assumption is that if the BIOS passes 0x01, etc, it's > garbage and should be ignored completely. I understand the assumption. > > That's > > something I'll rather not do without seeing the original bug reports. > > Same here. Maybe Okuji will know.. When I tried to actually change the code, it turned out that grub-mkimage doesn't change the boot sector, so grub-mkimage needs to be adjusted, and maybe some other tools. Alternatively, the logic should not be reverted, i.e. the adjustments should be done for the hard drive installs. This means that grub-setup should write valid x86 code over NOPs. It gets too complicated to bother without having a very good incentive to save those 2 bytes. -- Regards, Pavel Roskin