[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2 3/5] target-arm: convert sar, shl and shr hel
From: |
Aurelien Jarno |
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 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, Sep 25, 2012 at 02:57:20PM +0100, Peter Maydell wrote:
> On 21 September 2012 20:33, Aurelien Jarno <address@hidden> 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
address@hidden http://www.aurel32.net
- [Qemu-devel] [PATCH v2 0/5] target-arm: misc optimizations, Aurelien Jarno, 2012/09/21
- [Qemu-devel] [PATCH v2 5/5] target-arm: use deposit instead of hardcoded version, Aurelien Jarno, 2012/09/21
- [Qemu-devel] [PATCH v2 2/5] target-arm: convert add_cc and sub_cc helpers to TCG, Aurelien Jarno, 2012/09/21
- [Qemu-devel] [PATCH v2 3/5] target-arm: convert sar, shl and shr helpers to TCG, Aurelien Jarno, 2012/09/21
- [Qemu-devel] [PATCH v2 1/5] target-arm: use globals for CC flags, Aurelien Jarno, 2012/09/21
- [Qemu-devel] [PATCH v2 4/5] target-arm: mark a few integer helpers const and pure, Aurelien Jarno, 2012/09/21
- Re: [Qemu-devel] [PATCH v2 0/5] target-arm: misc optimizations, Peter Maydell, 2012/09/25