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Date: Fri, 29 Aug 2008 12:46:03 +0200
From: Thiemo Seufer <ths@networkno.de>
Subject: Re: [Qemu-devel] [5100] SH4: Convert register moves to TCG
Message-ID: <20080829104603.GE3229@networkno.de>
References: <E1KYoda-0004vn-QQ@cvs.savannah.gnu.org>
	<200808282313.42947.paul@codesourcery.com>
	<20080828232353.GA10605@volta.aurel32.net>
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To: Aurelien Jarno <aurelien@aurel32.net>
Cc: qemu-devel@nongnu.org

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)
> > > +{
> > > + =A0 =A0tcg_gen_st_tl(t, cpu_env, offsetof(CPUState, gregs[reg]));
> >=20
> > The preferred way of doing this is to have TCG variables for common (po=
ssibly=20
> > all?) registers. See e.g. m68k or sparc.
> >=20
>=20
> 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.

For MIPS I tried to keep thing similiar to dyngen when both TCG and
dyngen were used. Then I converted a few places to use TCG variables
but had no time to finish the job.

> I wonder in which way what your propose is better? It seems easier to wri=
te,
> but what about the runtime speed?

TCG variables are (potentially) better.


Thiemo