From owner-freebsd-hackers Fri Nov 8 8:41:34 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 10E0F37B401 for ; Fri, 8 Nov 2002 08:41:33 -0800 (PST) Received: from mail.speakeasy.net (mail11.speakeasy.net [216.254.0.211]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9D93643E3B for ; Fri, 8 Nov 2002 08:41:32 -0800 (PST) (envelope-from jhb@FreeBSD.org) Received: (qmail 20493 invoked from network); 8 Nov 2002 16:41:30 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail11.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 8 Nov 2002 16:41:30 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.6/8.12.6) with ESMTP id gA8Geqn5060356; Fri, 8 Nov 2002 11:40:59 -0500 (EST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200211081007.gA8A7fwx000751@apollo.backplane.com> Date: Fri, 08 Nov 2002 11:40:52 -0500 (EST) From: John Baldwin To: Matthew Dillon Subject: RE: Int 0x15 and VM86 question Cc: hackers@freebsd.org Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 08-Nov-2002 Matthew Dillon wrote: > I've been pulling my hair out all night trying to figure out how > the hell the VM86 code is able to issue an int 0x15 to the BIOS. > I can't find where it gets the interrupt descriptor table entry > for int 0x15. My assumption is that it copies it from the idt > supplied by the BIOS but I don't see where. As far as I can tell > FreeBSD loads a pristine IDT that does not have a record for > int 0x15. So how can the VM86 code issue an int 0x15 and have it > find the BIOS? > > If anyone knows the answer to this, I'm all ears! I think we use a different IDT for vm86 mode that is basically a duplicate (if not the original) of the BIOS IDT. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message