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Re: [Qemu-devel] Switch to OpenBIOS for Sparc32/64?

From: Fabrice Bellard
Subject: Re: [Qemu-devel] Switch to OpenBIOS for Sparc32/64?
Date: Wed, 14 Jun 2006 14:22:53 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20040913

Blue Swirl wrote:

I included other fixes currently needed for correct operation (clock year fix, FPU fix by Joerg Platte, MMU no-fault fix).

Note: the FPU "fix" should be revisited because it is really not optimal. Here are some ideas to implement it better:

1) Include the bit 'psref' in the static translation state (in tb->flags). Then psref can be tested at translation time and there is no run time cost. This approach is used on the x86 target. The downside is that two TBs may be generated for a given block of code depending on the psref value. Ideally if no FPU operations are used in the TB, psref should be ignored (not done yet on x86).

2) Keep psref dynamic, but test it only once per TB using FPU operations. In case of exception, rebuilt the CPU state as with MMU exceptions so that save_state() is not needed.

I tend to prefer the solution (1).


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