Messages in this thread | | | Date | Tue, 19 Sep 2006 01:14:31 +0200 | From | "Jesper Juhl" <> | Subject | Re: Math-emu kills the kernel on Athlon64 X2 |
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On 19/09/06, Linus Torvalds <torvalds@osdl.org> wrote: > > > On Tue, 19 Sep 2006, Jesper Juhl wrote: > > > > If I enable the math emulator in 2.6.18-rc7-git2 (only version I've > > tried this with) and then boot the kernel with "no387" then I only get > > as far as lilo's "...Booting the kernel." message and then the system > > hangs. > > I'm wondering if it tries to use the MMX/XMM stuff for memcpy and friends. > > I'm also wondering why you'd be doing what you seem to try to be doing in > the first place ;) > Simply to try and find bugs. If we have a math emulator and it's selectable for my CPU type, then it should damn well work ;-)
> Basically, "no387" doesn't seem to disable any of the fancier FPU > features, even though it obviously should. If you ask for math emulation, > you'll get emulation faults for _all_ of the modern MMX stuff too (which > we don't do). > Hmm, I guess that could be the problem. The emulator should disable any stuff which it's not able to handle. I've not actually looked very much at the emulator code yet, so I didn't realize it didn't disable what it couldn't handle, but getting it to do that sounds like a sensible first step.
> It's entirely possible that nobody has ever tested this combination. > That was my thought as well, which is exactely why I chose to try it - thinking that it might expose some bugs in math-emu or elsewhere.
-- Jesper Juhl <jesper.juhl@gmail.com> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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