From: Aurelien Jarno <aurelien@aurel32.net>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v2 3/5] target-arm: convert sar, shl and shr helpers to TCG
Date: Wed, 26 Sep 2012 00:41:34 +0200 [thread overview]
Message-ID: <20120925224134.GA24473@ohm.aurel32.net> (raw)
In-Reply-To: <CAFEAcA-QE3bVW-KdBQ_uf9grXu34x-mXGnxyTd_rmd7dGd1j7g@mail.gmail.com>
On Tue, Sep 25, 2012 at 02:57:20PM +0100, Peter Maydell wrote:
> On 21 September 2012 20:33, Aurelien Jarno <aurelien@aurel32.net> wrote:
> > +static void gen_sar(TCGv dest, TCGv t0, TCGv t1)
> > +{
> > + TCGv tmp1, tmp2, tmp3;
> > + tmp1 = tcg_temp_new_i32();
> > + tcg_gen_andi_i32(tmp1, t1, 0xff);
> > + tmp2 = tcg_const_i32(0x1f);
> > + tmp3 = tcg_const_i32(0);
> > + tcg_gen_movcond_i32(TCG_COND_GTU, tmp1, tmp1, tmp2, tmp2, tmp1);
> > + tcg_temp_free_i32(tmp3);
> > + tcg_temp_free_i32(tmp2);
> > + tcg_gen_andi_i32(tmp1, tmp1, 0x1f);
> > + tcg_gen_sar_i32(dest, t0, tmp1);
> > + tcg_temp_free_i32(tmp1);
> > +}
>
> I don't think you need the "tcg_gen_andi_i32(tmp1, tmp1, 0x1f);"
> for sar, do you? The movcond is doing "shift = (shift > 31) ? 31 : shift"
> so we know it's going to be in [0..31] and the and will do nothing,
> right?
>
Indeed, that's a leftover from the previous version based on setcond.
It should be removed.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
next prev parent reply other threads:[~2012-09-25 22:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 19:33 [Qemu-devel] [PATCH v2 0/5] target-arm: misc optimizations Aurelien Jarno
2012-09-21 19:33 ` [Qemu-devel] [PATCH v2 1/5] target-arm: use globals for CC flags Aurelien Jarno
2012-09-25 16:40 ` Peter Maydell
2012-09-21 19:33 ` [Qemu-devel] [PATCH v2 2/5] target-arm: convert add_cc and sub_cc helpers to TCG Aurelien Jarno
2012-09-25 16:40 ` Peter Maydell
2012-09-21 19:33 ` [Qemu-devel] [PATCH v2 3/5] target-arm: convert sar, shl and shr " Aurelien Jarno
2012-09-21 23:14 ` Richard Henderson
2012-09-22 9:33 ` Aurelien Jarno
2012-09-25 13:57 ` Peter Maydell
2012-09-25 22:41 ` Aurelien Jarno [this message]
2012-09-21 19:33 ` [Qemu-devel] [PATCH v2 4/5] target-arm: mark a few integer helpers const and pure Aurelien Jarno
2012-09-25 16:40 ` Peter Maydell
2012-09-21 19:33 ` [Qemu-devel] [PATCH v2 5/5] target-arm: use deposit instead of hardcoded version Aurelien Jarno
2012-09-25 16:41 ` Peter Maydell
2012-09-25 16:39 ` [Qemu-devel] [PATCH v2 0/5] target-arm: misc optimizations Peter Maydell
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