From owner-freebsd-hackers Tue Jul 17 14:49:14 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from meow.osd.bsdi.com (meow.osd.bsdi.com [204.216.28.88]) by hub.freebsd.org (Postfix) with ESMTP id 3B92C37B431 for ; Tue, 17 Jul 2001 14:49:10 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by meow.osd.bsdi.com (8.11.4/8.11.2) with ESMTP id f6HLmmv94152; Tue, 17 Jul 2001 14:48:49 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <20010717095413.G83710-100000@wonky.feral.com> Date: Tue, 17 Jul 2001 14:48:58 -0700 (PDT) From: John Baldwin To: Matthew Jacob Subject: RE: x86 unaligned access followup. Cc: hackers@FreeBSD.org, Terry Lambert 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 17-Jul-01 Matthew Jacob wrote: > > >> Actually, since the 486, it's been possible for us to turn on unaligned >> access exceptions on the x86. We should probably consider doing this, to >> ensure better performance, and to avoid the unnecessary bus overhead we >> eat for unaligned access today... not to mention how it could shake out >> the drivers. > > > Now *that* is a very cool idea. As Johnny Carson would say "I did not know > that". How would this be done? I assume it's some bit-flip for the chip? > D'ya have a sample bit 'o code for this? It's the AC bit in eflags. > -matt -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "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