From owner-freebsd-arch Mon Jan 7 13:41:40 2002 Delivered-To: freebsd-arch@freebsd.org Received: from ns.yogotech.com (ns.yogotech.com [206.127.123.66]) by hub.freebsd.org (Postfix) with ESMTP id 066CC37B404; Mon, 7 Jan 2002 13:41:36 -0800 (PST) Received: from caddis.yogotech.com (caddis.yogotech.com [206.127.123.130]) by ns.yogotech.com (8.9.3/8.9.3) with ESMTP id OAA18156; Mon, 7 Jan 2002 14:41:31 -0700 (MST) (envelope-from nate@yogotech.com) Received: (from nate@localhost) by caddis.yogotech.com (8.11.6/8.11.6) id g07LfVm00350; Mon, 7 Jan 2002 14:41:31 -0700 (MST) (envelope-from nate) From: Nate Williams MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15418.5641.919327.356015@caddis.yogotech.com> Date: Mon, 7 Jan 2002 14:41:29 -0700 To: jhb@freebsd.org Cc: Nate Williams , Dan Eischen , arch@freebsd.org Subject: Re: Request for review: getcontext, setcontext, etc In-Reply-To: References: <15418.4935.657413.312252@caddis.yogotech.com> X-Mailer: VM 6.96 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid Reply-To: nate@yogotech.com (Nate Williams) Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > > Also, forgive my ignorance, but why are we using fnsave instead of > > fsave? From my reading of the x86 manuals, it would seem that there is > > the possibility of getting bogus FPU results with fnsave (vs. fsave) > > since by using fsave, we give the FPU a chance to finish up the current > > FPU operations before we save the state? I could see where they might > > be a race where we might end up storing intermediate results of the FPU > > in some instances. > > > > Or, is there something else I'm missing? (The reason I ask is that the > > JDK uses fsave to be 'safe', but maybe it's not buying us anything other > > than warm fuzzies. :) > > I don't know :-) That's what it was using when John Birrell was > maintaining libc_r. I can always change it... How about it John? Why the use of 'fnsave' when storing FPU context vs. using fsave? Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message