From owner-freebsd-questions Wed Jun 30 20:14:53 1999 Delivered-To: freebsd-questions@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id C8C7B14E60; Wed, 30 Jun 1999 20:14:34 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id MAA02604; Thu, 1 Jul 1999 12:44:31 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id MAA82696; Thu, 1 Jul 1999 12:44:31 +0930 (CST) Date: Thu, 1 Jul 1999 12:44:31 +0930 From: Greg Lehey To: Hui Huang Cc: FreeBSD Hackers Subject: Re: Could I do floating point calculation in the kernel program? Message-ID: <19990701124431.N79211@freebie.lemis.com> References: <377B21AB.D11FE5C3@ntc.nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <377B21AB.D11FE5C3@ntc.nokia.com>; from Hui Huang on Thu, Jul 01, 1999 at 11:07:08AM +0300 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG [moved to -hackers] On Thursday, 1 July 1999 at 11:07:08 +0300, Hui Huang wrote: > I want to add some floating point calculation functions in FreeBSD > kernel program. > I compiled the new kernel and installed it in a machine. However, the > new kernel could not be booted up with the error information "Fatal trap > > 22: FPU device not available while in kernel mode". > Does anybody know how to enable the FPU device in the kernel mode or > other methods to support floating point calculation in the kernel mode? This is probably more appropriate in -hackers than in -questions, so I've moved it there. Basically, you can't do this. In order to support FP in the kernel, the system would need to save FP state for every context switch, which would be a serious performance hit. Why do you need FP? Do you really need FP? Greg -- When replying to this message, please copy the original recipients. For more information, see http://www.lemis.com/questions.html See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message