From owner-freebsd-arch Fri Jan 25 14:57:10 2002 Delivered-To: freebsd-arch@freebsd.org Received: from pcnet1.pcnet.com (pcnet1.pcnet.com [204.213.232.3]) by hub.freebsd.org (Postfix) with ESMTP id CE43637B400 for ; Fri, 25 Jan 2002 14:57:07 -0800 (PST) Received: (from eischen@localhost) by pcnet1.pcnet.com (8.12.1/8.12.1) id g0PMtkUA005818; Fri, 25 Jan 2002 17:55:46 -0500 (EST) Date: Fri, 25 Jan 2002 17:55:46 -0500 (EST) From: Daniel Eischen To: Nate Williams Cc: Terry Lambert , Dan Eischen , k Macy , Peter Wemm , Julian Elischer , arch@FreeBSD.ORG Subject: Re: KSE question In-Reply-To: <15441.56832.170618.611705@caddis.yogotech.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 On Fri, 25 Jan 2002, Nate Williams wrote: > > > The FPU usage is problematic, but is also resolvable, as a > > > tools issue. > > > > > > Specifically, if an ELF section were generated whenever > > > the compiler generated FPU code (let's call this section > > > "flags", for the sake of argument), then the flag "FPU=1" > > > could be set there. > > > > [ ... ] > > > > Interesting. I think we only care about FPU state > > during signal deliver and preemptions though, and in > > that case, the kernel can just pass us the "FPU used" > > flag and/or "FPU format" along with the interrupted > > context. > > There's lots of talk about using this 'FPU used' flag, but at least my > read of things from the long discussion before was that it may not be > possible to implement this on the x86 architectures we currently > support. > > It sounds like a great idea, *IF* if can be done. The kernel knows if the FPU has been used and it also knows the format (x87 vs SSE/XMM). As long as the FPU context comes from the kernel, then it can also tell us whether it is valid and it's format. I'm reworking [gs]etcontext; let's hold off on this for a bit and I'll post the changes. -- Dan Eischen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message