Re: [Qemu-devel] [Question] Qemu Register Mapping Directly in AARCH64

[Peter Maydell]

On 9 June 2014 06:59, Chaos Shu <address@hidden> wrote:
> I’ve noticed that Qemu maintained the target arch register in memory for
> capacity, but the load/store really cost a bit much, is there any way map
> the register directly.

Our JIT's register allocator will avoid storing the guest register value
back to RAM unless it has to (eg if we might be about to fault,
call a helper which would trash the host register, etc).
Using a target-agnostic JIT like this is a pretty fundamental design
decision that isn't easy to change. In any case the regs[] array
in the CPU state struct will always be in L1 cache so access will
be fast.

thanks
-- PMM