From owner-freebsd-amd64@FreeBSD.ORG Wed Feb 27 14:00:54 2008 Return-Path: Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 83789106566B for ; Wed, 27 Feb 2008 14:00:54 +0000 (UTC) (envelope-from cineveggie.lists@gmail.com) Received: from rv-out-0910.google.com (rv-out-0910.google.com [209.85.198.191]) by mx1.freebsd.org (Postfix) with ESMTP id 5B1BB8FC1A for ; Wed, 27 Feb 2008 14:00:54 +0000 (UTC) (envelope-from cineveggie.lists@gmail.com) Received: by rv-out-0910.google.com with SMTP id g13so1983115rvb.43 for ; Wed, 27 Feb 2008 06:00:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:from:to:in-reply-to:content-type:content-transfer-encoding:mime-version:subject:date:references:x-mailer; bh=eR2nkavjnAtYsEeW/LUbZ8lMQxG6qqWs3478vkzkvhM=; b=WZwAzhF2Nesnt1ByQoJAYLnBq/ErVRTy4UBKfHalNbMpskzAT+Lp3e9uMyb34wBpANMZW5qjsQu+827MIMCaweoIhKWp7et4MLcN0eU+UorV1+rfOHJJI6iizP2mX5iOILczICR8xqwm/+oLACLUw1NY+JCqNZqheiMNBGALcAc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:from:to:in-reply-to:content-type:content-transfer-encoding:mime-version:subject:date:references:x-mailer; b=Sjp9ulSZ8rZWGHBD5M0SrMN/DiiMF9ow7FEFnZa2i5kYM5n096DO3B5Qm9iZcZbRTB1VUV87Po3CWHbgIsHAz+xcK1qREPTggZF4j997rmzPHiyrGfA1P+87OazroEINhY90Kuonrc7+rH4qXE37MHtMMBwqUOBqVAGEvV1YruU= Received: by 10.141.79.12 with SMTP id g12mr4495229rvl.182.1204119291826; Wed, 27 Feb 2008 05:34:51 -0800 (PST) Received: from ?10.0.1.3? ( [66.69.216.112]) by mx.google.com with ESMTPS id i4sm10540151rng.7.2008.02.27.05.34.50 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 27 Feb 2008 05:34:50 -0800 (PST) Message-Id: <443D814E-04F3-411C-9DF9-E799A39FAEB3@gmail.com> From: Jeff Isaac To: freebsd-amd64@freebsd.org In-Reply-To: Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v919.2) Date: Wed, 27 Feb 2008 07:34:48 -0600 References: X-Mailer: Apple Mail (2.919.2) Subject: Re: "freebsd-amd64" X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Feb 2008 14:00:54 -0000 On Feb 27, 2008, at 6:42 AM, Pete French wrote: > "So the SMAP problem is that in the one BIOS I looked at, the SMAP > BIOS call > only works from real mode. Even if invoked from virtual 86 mode, > the BIOS > call fails. FreeBSD only calls the BIOS SMAP call from virtual 86 > mode both > in the loader and in the i386 kernel. The fix is quite complicated > and > involves rewriting the boot code to invoke BIOS calls from real mode > rather > than virtual 86 mode." Forgive me if this has already been asked, but I'm in the process of trying to teach myself some of the basics for the loader and boot, etc... on the powerpc port. I realize that this is platform specific and probably has zero bearing on anything I code specifically (since I'll have firmware to doodle with, not BIOS), BUT, from a general knowledge perspective, what advantages does virtual 86 mode have over real mode? Essentially, why did the FreeBSD project choose the virtual implementation? More portable? Easier to write? None of the above? Thanks! :) - Jeff