Date: Fri, 25 Jan 2002 22:36:30 -0700 From: Nate Williams <nate@yogotech.com> To: Terry Lambert <tlambert2@mindspring.com> Cc: Nate Williams <nate@yogotech.com>, Daniel Eischen <eischen@pcnet1.pcnet.com>, Dan Eischen <eischen@vigrid.com>, k Macy <kip_macy@yahoo.com>, Peter Wemm <peter@wemm.org>, Julian Elischer <julian@vicor-nb.com>, arch@FreeBSD.ORG Subject: Re: KSE question Message-ID: <15442.16478.408033.680185@caddis.yogotech.com> In-Reply-To: <3C51FF0A.9ACAC316@mindspring.com> References: <3C51D0B6.F6E04EBC@mindspring.com> <Pine.SUN.3.91.1020125164325.24428A-100000@pcnet1.pcnet.com> <15441.56832.170618.611705@caddis.yogotech.com> <3C51E888.FD13A18D@mindspring.com> <15441.59691.361172.394760@caddis.yogotech.com> <3C51F18A.C0D8D6B1@mindspring.com> <15441.62092.864056.841853@caddis.yogotech.com> <3C51F492.CB0FB69E@mindspring.com> <15441.62830.180895.121111@caddis.yogotech.com> <3C51F89E.78DAD01D@mindspring.com> <15441.63876.271856.290838@caddis.yogotech.com> <3C51FF0A.9ACAC316@mindspring.com>
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> > > > Otherwise known as not having a complete solution to the problem, hence > > > > not having a solution at all. :( > > > > > > It maps the problem space, so it's a complete solution. > > > > No, it doesn't. It's a 75% solution, and the remaining 25% is extremely > > common. Not an acceptable solution. > > FPU usage is uncommon. If it were 51% common, we'd just pay > the cost of switching it all the time, and this discussion > would not have started. Depends on what you consider common. I'll bet that a significant percentage of programs use the FPU. However, they use the FPU *very* little in the total amount of time used. So, even if they use it once, that's enough to cause problems if you don't handle it correctly. > > Plus, it's not possible to do, since there are no 'Good' java->native > > code compilers for FreeBSD. (There is only one decent compiler out, and > > it isn't ported to FreeBSD. And, GCC is *NOT* that compiler, as it's > > Java stuff isn't useful for anything real.) > > 8^). We agree on two things, now. 8-) 8-). Wow. Better write it on my calendar. > > > Cool! Let's just dike the thing out! > > > > > > I know, we can compile the FPU emulation library into user > > > space, and not use the hardware FPU at all. Then we can fix > > > the emulated FPU, and the problem goes away. 8-) 8-) 8-). > > > > Yeah, sure. > > How about this: force trigger the exception before context > switching away, if the FPU has been used. Again, the issue is that we can't determine *IF* the FPU has been used effeciently. All solutions assume this solution, although Daniel's may have a way of short-circuiting this in the short term. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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