Re: Emulating unsupported x86 opcodes in software

[Stefan Seidel]

On Wed, Jan 25, 2012 at 13:17, Mikael Pettersson <mikpe@xxxxxxxx> wrote:
> Just two general comments, not specifically related to emulating SSE3:
>
> 1. Deploying the emulator from userspace would be preferable.  LD_PRELOAD a
>   library containing the SSE3 emulation and init code to set up a SIGILL
>   handler.  This solves all the ring 0 vs 3 problems and avoids needing
>   any kernel modifications.
Thanks for the hint. I knew that this would be a possiblity, but I
don't think it's wise or possible to run _every_ binary that could
possibly be started on the machine with this technique - hence the
kernel integration.

> 2. It's not always the case that new instructions in later generation x86
>   processors trap in earlier generation processors.  E.g., several years
I think that's not a problem in the processor generation I target. The
said emulation has been used successfully on a lot of machines running
MacOS X, and this included the use of heavy multi-media apps which
actually use these intructions a lot.

Stefan
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