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[Qemu-devel] [PATCH 0/4] target-ppc: create TCG slots for registers base
[Qemu-devel] [PATCH 0/4] target-ppc: create TCG slots for registers based on CPU
Sat, 28 Mar 2009 14:30:13 -0700
For PPC guests, I noticed that we create TCG slots for all the potential
kinds of registers (float, Altivec, SPE), even if the chip doesn't have
instructions to access those registers.
This patch series tweaks the initialization routine to create the TCG
values for registers necessary for particular classes of instructions
only if the emulated chip supports those instructions. The first couple
of patches are simply busywork of moving things around; the last patch
is where all the action is at.
I am not a TCG expert, but there are several loops in TCG over all
globals and it seems like those loops would go faster if they didn't
have to consider registers that would never be touched. If this patch
series makes no difference in TCG's performance, then I'd be glad to
have an explanation of why that's the case.