From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [5100] SH4: Convert register moves to TCG
Date: Fri, 29 Aug 2008 01:12:12 +0100 [thread overview]
Message-ID: <200808290112.13308.paul@codesourcery.com> (raw)
In-Reply-To: <20080828232353.GA10605@volta.aurel32.net>
On Friday 29 August 2008, Aurelien Jarno wrote:
> On Thu, Aug 28, 2008 at 11:13:42PM +0100, Paul Brook wrote:
> > On Thursday 28 August 2008, Aurelien Jarno wrote:
> > > +static always_inline void gen_movl_T_rN (TCGv t, int reg)
> > > +{
> > > + tcg_gen_st_tl(t, cpu_env, offsetof(CPUState, gregs[reg]));
> >
> > The preferred way of doing this is to have TCG variables for common
> > (possibly all?) registers. See e.g. m68k or sparc.
>
> Until now I have used MIPS as an example, it copies CPU registers to TCG
> variables. As you pointed, m68k and sparc use direct access to CPU
> registers through TCG variables.
>
> I wonder in which way what your propose is better? It seems easier to
> write, but what about the runtime speed?
I'm guessing that with current tcg there's not a lot of difference. Using
variables (like sparc/m68k) gives scope for better/easier code generation in
the future, and makes debug dumps look prettier.
Paul
next prev parent reply other threads:[~2008-08-29 0:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-28 21:02 [Qemu-devel] [5100] SH4: Convert register moves to TCG Aurelien Jarno
2008-08-28 22:13 ` Paul Brook
2008-08-28 23:23 ` Aurelien Jarno
2008-08-29 0:12 ` Paul Brook [this message]
2008-08-29 10:46 ` Thiemo Seufer
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