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From: Fabrice Bellard <fabrice@bellard.org>
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Subject: [Qemu-devel] Re: [PATCH, RFC, WIP] TCG for Qemu target Sparc32/64
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To: Blue Swirl <blauwirbel@gmail.com>
Cc: qemu-devel@nongnu.org

> [...]
>>  Another point is that you should define TCG globals for each SPARC GPR.
>>  It was not done for i386 because I feared performance regressions when
>>  accessing to 16 bit or 8 bit sub-registers. On SPARC you do not have
>>  this issue.
> 
> Nice idea. Would this also work for windowed registers?

Yes, provided you use a fixed register to store regwptr. Then you can
define the windowed registers as globals using this register as base.

The real problem is to save and restore this register in cpu_exec() and
in all the places where the regwptr CPU state field is accessed
directly. TCG will handle these problems generically soon, but before it
does it you can implement it "by hand".

Regards,

Fabrice.