From owner-freebsd-hackers@FreeBSD.ORG Thu May 31 08:48:00 2007 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A57B016A469 for ; Thu, 31 May 2007 08:48:00 +0000 (UTC) (envelope-from rmgls@orange.fr) Received: from smtp19.orange.fr (smtp19.orange.fr [80.12.242.17]) by mx1.freebsd.org (Postfix) with ESMTP id 6ED2B13C448 for ; Thu, 31 May 2007 08:48:00 +0000 (UTC) (envelope-from rmgls@orange.fr) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf1907.orange.fr (SMTP Server) with ESMTP id 9B6791C000A5; Thu, 31 May 2007 10:47:55 +0200 (CEST) Received: from orange.fr (ARouen-153-1-50-12.w90-17.abo.wanadoo.fr [90.17.233.12]) by mwinf1907.orange.fr (SMTP Server) with ESMTP id 816A61C0008F; Thu, 31 May 2007 10:47:55 +0200 (CEST) X-ME-UUID: 20070531084755530.816A61C0008F@mwinf1907.orange.fr From: rmgls@wanadoo.fr To: Mike Meyer Date: Thu, 31 May 2007 10:47:54 +0200 Sender: rmgls@orange.fr Message-Id: <20070531084755.816A61C0008F@mwinf1907.orange.fr> Cc: freebsd-hackers@freebsd.org Subject: Re: direct I/O access X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 May 2007 08:48:00 -0000 On Wed, 30 May 2007 12:39:10 -0400, Mike Meyer wrote, > Actually, protected mode is just the beginnings of it. I've never done > much x86 assembly, but going from the '020 to the '030 (or maybe it > was the '010 to the '020). I had to start invalidating the hardware > caches after certain operations. After that, I switched to RISC > hardware, which were designed assuming that the real people writing > assembler would be few and far between, and did crazy things like > rearrange the instruction sequence behind your back and add extra > instructions. Modern systems do this kind of stuff as well. do you think that it would be better to rewrite the soft in C??? in this case, i have more work to do! first of all, learning C on the finger tip, before working on my soft. and i thought that it would be very interesting to learn the heart of FreeBSD. > This really is a kludge, though. You haven't said what you're trying > to do. If you're trying to keep an old one-of device working, this is > probably the best way. But if it's a real device that other people > might be using, then writing a real device driver, or seeing if you > can make the device work with something like the iic drivers might be > better. in fact, they are: - a direct to disk recorder, - a sampler. they are not usable by other people, because they were discontinued. bests regards raoul rmgls@wanadoo.fr