From: Peter Maydell <peter.maydell@linaro.org>
To: Chaos Shu <chaos.shun@live.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [Question] Qemu Register Mapping Directly in AARCH64
Date: Mon, 9 Jun 2014 08:51:45 +0100 [thread overview]
Message-ID: <CAFEAcA-ghXYow6mt48TmiLk7O4VSK7oAhPmBS6QGXTa=8L6C7A@mail.gmail.com> (raw)
In-Reply-To: <SNT149-DS19931E4D1C708520E5BC47FB290@phx.gbl>
On 9 June 2014 06:59, Chaos Shu <chaos.shun@live.com> 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
prev parent reply other threads:[~2014-06-09 7:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-09 5:59 [Qemu-devel] [Question] Qemu Register Mapping Directly in AARCH64 Chaos Shu
2014-06-09 7:51 ` Peter Maydell [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAFEAcA-ghXYow6mt48TmiLk7O4VSK7oAhPmBS6QGXTa=8L6C7A@mail.gmail.com' \
--to=peter.maydell@linaro.org \
--cc=chaos.shun@live.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).