From owner-freebsd-smp Mon Dec 2 02:16:55 1996 Return-Path: owner-smp Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id CAA14366 for smp-outgoing; Mon, 2 Dec 1996 02:16:55 -0800 (PST) Received: from zwei.siemens.at (zwei.siemens.at [193.81.246.12]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id CAA14361 for ; Mon, 2 Dec 1996 02:16:50 -0800 (PST) Received: from sol1.gud.siemens.co.at (root@[10.1.143.100]) by zwei.siemens.at (8.7.5/8.7.3) with SMTP id LAA15986 for ; Mon, 2 Dec 1996 11:16:08 +0100 (MET) Received: from ws2301.gud.siemens.co.at by sol1.gud.siemens.co.at with smtp (Smail3.1.28.1 #7 for ) id m0vUVPx-0001y9C; Mon, 2 Dec 96 11:16 MET Received: by ws2301.gud.siemens.co.at (1.37.109.16/1.37) id AA243241632; Mon, 2 Dec 1996 11:13:52 +0100 From: "Hr.Ladavac" Message-Id: <199612021013.AA243241632@ws2301.gud.siemens.co.at> Subject: Re: Pentium CPU steppings To: phk@critter.tfs.com (Poul-Henning Kamp) Date: Mon, 2 Dec 1996 11:13:52 +0100 (MEZ) Cc: peter@spinner.dialix.com, freebsd-smp@freebsd.org In-Reply-To: <3057.849292563@critter.tfs.com> from "Poul-Henning Kamp" at Nov 29, 96 07:36:03 pm X-Mailer: ELM [version 2.4 PL24 ME8a] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk E-mail message from Poul-Henning Kamp contained: > > In message <199611291828.CAA19491@spinner.DIALix.COM>, Peter Wemm writes: > >Poul-Henning Kamp wrote: > >> >Hmm, I wonder if it's safe to test for this at the end of npx.c in the > >> >kernel? > >> > >> Linux can do it, so why couldn't we ? > > > >Yeah, but have you ever seen it report "yes"? Last I checked, (2.0.twenty > >something), the code looked very much like it hardwired the "fdiv bug > >present?" result to "no" and I could not find any code in the kernel that > > yes, they circumvent it, I belive in their compiler :-) But do they circumvent it in all instances? According to c't magazine, Intel admitted that some other operations that internally use FDIV are also buggy. From the top of my head: ATAN ATAN2 and about 5 or 6 others. N.B. the interpolation trick does not help at all if you use these (and practically all of ray-tracing software does ): /Marino > > -- > Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. > http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. > whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc. > Future will arrive by its own means, progress not so. >