From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1MIrJv-0005Vu-I6 for mharc-grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:55 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MIrJt-0005UC-HL for grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:53 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MIrJo-0005OH-Ko for grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:53 -0400 Received: from [199.232.76.173] (port=48111 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MIrJo-0005O6-EZ for grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:48 -0400 Received: from mx20.gnu.org ([199.232.41.8]:27333) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MIrJn-0005B5-8a for grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:48 -0400 Received: from c60.cesmail.net ([216.154.195.49]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MIrJm-0004ZO-9l for grub-devel@gnu.org; Mon, 22 Jun 2009 17:44:46 -0400 Received: from unknown (HELO smtprelay2.cesmail.net) ([192.168.1.112]) by c60.cesmail.net with ESMTP; 22 Jun 2009 17:44:45 -0400 Received: from [192.168.0.22] (static-72-92-88-10.phlapa.fios.verizon.net [72.92.88.10]) by smtprelay2.cesmail.net (Postfix) with ESMTPSA id 422AA34C6A for ; Mon, 22 Jun 2009 17:50:55 -0400 (EDT) From: Pavel Roskin To: The development of GRUB 2 In-Reply-To: <20090622213232.GB10027@thorin> References: <20090621181748.GA21152@thorin> <20090621225332.GB2360@thorin> <1245633761.9864.34.camel@mj> <20090622095252.GC8969@thorin> <1245699543.2561.1.camel@mj> <20090622205213.GB7871@thorin> <20090622213232.GB10027@thorin> Content-Type: text/plain Date: Mon, 22 Jun 2009 17:44:43 -0400 Message-Id: <1245707083.5069.2.camel@mj> Mime-Version: 1.0 X-Mailer: Evolution 2.26.2 (2.26.2-1.fc11) Content-Transfer-Encoding: 7bit X-Detected-Operating-System: by mx20.gnu.org: Genre and OS details not recognized. X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Subject: Re: [PATCH] access gdtdesc on segment 0 unconditionally (Re: [PATCH] i386-qemu port) 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: Mon, 22 Jun 2009 21:44:53 -0000 On Mon, 2009-06-22 at 23:32 +0200, Robert Millan wrote: > On Mon, Jun 22, 2009 at 10:52:13PM +0200, Robert Millan wrote: > > I don't think it's possible to use relative addresses > > with this particular instruction. > > Uhm sorry, this was silly. Of course you can use addresses relative to a > segment in lgdt, but this doesn't change the fact that GAS always gives > you absolute ones. > > Also, I'm not sure if it's possible to use a 16-bit field in this instruction, > it could be that the field is always 32-bit, even if it's relative to a > segment. This dump is from the i386-pc kernel.img: > > 836f: 2e 67 66 0f 01 15 68 addr32 lgdtl %cs:0x8368 > 8376: 83 00 00 > > a little-endian 0x00008368 is seen here, indicating the field is 32-bit. But if I omit ADDR32, I get: 0000016e : 16e: fa cli 16f: 2e 66 0f 01 16 68 01 lgdtl %cs:0x168 176: 0f 20 c0 mov %cr0,%eax The address is 16-bit. -- Regards, Pavel Roskin