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Subject: Re: TSCs are a no-no on i386
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Matthew Garrett <mgarrett@chiark.greenend.org.uk>
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Date: 30 Jul 2003 18:19:26 +0100
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On Mer, 2003-07-30 at 17:58, Matthew Garrett wrote:
> g++ >=3.2 use 486-specific instructions in order to do atomic operations
> in C++ code. 3.3 includes a 386 version of the same code, but it's not
> possible to use a mixture of the two (ie, code compiled with a "486" g++
> will not work on the "386" version), and so to keep ABI compatibility
> with the other distributions it's necessary to break 386. The "obvious"
> solution (dragging this back on topic) is a kernel patch to emulate 486
> instructions on a 386.

You don't need to mash the kernel up for this - you can write yourself a
SIGILL handler to do the work - take a look at things like the pure
software MMX preloader someone wrote.