From owner-freebsd-hackers@FreeBSD.ORG Fri Mar 9 23:35:43 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 4073B16A400 for ; Fri, 9 Mar 2007 23:35:43 +0000 (UTC) (envelope-from deathjestr@gmail.com) Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.229]) by mx1.freebsd.org (Postfix) with ESMTP id F161613C442 for ; Fri, 9 Mar 2007 23:35:42 +0000 (UTC) (envelope-from deathjestr@gmail.com) Received: by wx-out-0506.google.com with SMTP id s18so943393wxc for ; Fri, 09 Mar 2007 15:35:42 -0800 (PST) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=YaGW59B6fLTnDhOPb+o9Pd0HTRgtzuFDeHl8MJZuPnw4TEcCJG5csmpKHhtLztJhY7wTDiinXEPpk2TgTaWtxkFeexGkvMnARzj9qozgnO2kVZvgeX/GycnVRHfshWLGgApgqGyssVv1bBRPIPyh5bGox9+9ADl97TYMgvsPfJ8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=JAdPmwM3ZhvWe8RmMlFPLf7bEbXa6/aqFghSEg7+zLCbhyUJSWV8jyzBwsOXI4exjyfsN+rZiVO/VqfebmBLOCK9z9l1Ub0ADoERYn3AKH9BTv69W8cLNG98F9/qcYTeRuxARvI+G+PpHfClIfXuMcXPfTCu8HFnguNZKzcP0Rg= Received: by 10.90.84.17 with SMTP id h17mr2528677agb.1173481825250; Fri, 09 Mar 2007 15:10:25 -0800 (PST) Received: by 10.90.78.13 with HTTP; Fri, 9 Mar 2007 15:10:25 -0800 (PST) Message-ID: <44b564930703091510r35e8c56eke0c8761fa5f234e9@mail.gmail.com> Date: Fri, 9 Mar 2007 18:10:25 -0500 From: "Michael M. Press" To: cokane@cokane.org, maslanbsd@gmail.com, freebsd-hackers@freebsd.org In-Reply-To: <346a80220703091044p5759e6do521065203299c26b@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <319cceca0703090116p7e768630qd055be57bbe4953@mail.gmail.com> <200703091021.l29ALLVw067285@lurza.secnetix.de> <346a80220703091044p5759e6do521065203299c26b@mail.gmail.com> Cc: Subject: Re: Floating-point in kernel space 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: Fri, 09 Mar 2007 23:35:43 -0000 > I think i've seen somewhere but i don't remember that floating point > arithmetic is not allowed in kernel space, if that's right, can anyone > please tell why ??? > and why not not emulate the floating point in kernel space ??? That's nonsense! Floating point arithmetic is absolutely allowed in kernel space, it's just that user space applications don't tend to like their data being mangled very much. I remember this topic coming up a short while ago on this list. Perhaps if there is sufficient need someone could implement a pair of floating-point save/restore functions to allow floating-point (or MMX) calculations to be used in the kernel only when needed. Something like the EngSaveFloatingPointState/ EngRestoreFloatingPointState functions that Windows has. --Mike