Date: Thu, 1 Jul 1999 12:44:31 +0930 From: Greg Lehey <grog@lemis.com> To: Hui Huang <hui.huang@ntc.nokia.com> Cc: FreeBSD Hackers <hackers@freebsd.org> Subject: Re: Could I do floating point calculation in the kernel program? Message-ID: <19990701124431.N79211@freebie.lemis.com> In-Reply-To: <377B21AB.D11FE5C3@ntc.nokia.com>; from Hui Huang on Thu, Jul 01, 1999 at 11:07:08AM %2B0300 References: <377B21AB.D11FE5C3@ntc.nokia.com>
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[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-hackers" in the body of the message
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