From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57081) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSI0L-0004ES-Ra for qemu-devel@nongnu.org; Wed, 27 Jul 2016 02:07:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bSI0J-0001eR-Ax for qemu-devel@nongnu.org; Wed, 27 Jul 2016 02:07:40 -0400 Date: Wed, 27 Jul 2016 15:19:04 +1000 From: David Gibson Message-ID: <20160727051904.GE17429@voom.fritz.box> References: <1469534318-5549-1-git-send-email-nikunj@linux.vnet.ibm.com> <1469534318-5549-8-git-send-email-nikunj@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="B3XPdYri2NuANWBV" Content-Disposition: inline In-Reply-To: <1469534318-5549-8-git-send-email-nikunj@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v4 07/15] target-ppc: implement branch-less divw[o][.] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nikunj A Dadhania Cc: qemu-ppc@nongnu.org, rth@twiddle.net, qemu-devel@nongnu.org, bharata@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com --B3XPdYri2NuANWBV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jul 26, 2016 at 05:28:30PM +0530, Nikunj A Dadhania wrote: > While implementing modulo instructions figured out that the > implementation uses many branches. Change the logic to achieve the > branch-less code. Undefined value is set to dividend in case of invalid > input. >=20 > Signed-off-by: Nikunj A Dadhania > --- > target-ppc/translate.c | 48 +++++++++++++++++++++++---------------------= ---- > 1 file changed, 23 insertions(+), 25 deletions(-) >=20 > diff --git a/target-ppc/translate.c b/target-ppc/translate.c > index 7c7328f..69d9ae0 100644 > --- a/target-ppc/translate.c > +++ b/target-ppc/translate.c > @@ -1049,41 +1049,39 @@ static void gen_addpcis(DisasContext *ctx) > static inline void gen_op_arith_divw(DisasContext *ctx, TCGv ret, TCGv a= rg1, > TCGv arg2, int sign, int compute_ov) > { > - TCGLabel *l1 =3D gen_new_label(); > - TCGLabel *l2 =3D gen_new_label(); > - TCGv_i32 t0 =3D tcg_temp_local_new_i32(); > - TCGv_i32 t1 =3D tcg_temp_local_new_i32(); > + TCGv_i32 t0 =3D tcg_temp_new_i32(); > + TCGv_i32 t1 =3D tcg_temp_new_i32(); > + TCGv_i32 t2 =3D tcg_temp_new_i32(); > + TCGv_i32 t3 =3D tcg_temp_new_i32(); > =20 > tcg_gen_trunc_tl_i32(t0, arg1); > tcg_gen_trunc_tl_i32(t1, arg2); > - tcg_gen_brcondi_i32(TCG_COND_EQ, t1, 0, l1); > - if (sign) { > - TCGLabel *l3 =3D gen_new_label(); > - tcg_gen_brcondi_i32(TCG_COND_NE, t1, -1, l3); > - tcg_gen_brcondi_i32(TCG_COND_EQ, t0, INT32_MIN, l1); > - gen_set_label(l3); > - tcg_gen_div_i32(t0, t0, t1); > - } else { > - tcg_gen_divu_i32(t0, t0, t1); > - } > - if (compute_ov) { > - tcg_gen_movi_tl(cpu_ov, 0); > - } > - tcg_gen_br(l2); > - gen_set_label(l1); > if (sign) { > - tcg_gen_sari_i32(t0, t0, 31); > + tcg_gen_setcondi_i32(TCG_COND_EQ, t2, t0, INT_MIN); > + tcg_gen_setcondi_i32(TCG_COND_EQ, t3, t1, -1); > + tcg_gen_and_i32(t2, t2, t3); > + tcg_gen_setcondi_i32(TCG_COND_EQ, t3, t1, 0); > + tcg_gen_or_i32(t2, t2, t3); > + tcg_gen_movi_i32(t3, 0); > + tcg_gen_movcond_i32(TCG_COND_NE, t1, t2, t3, t2, t1); > + tcg_gen_div_i32(t3, t0, t1); > + tcg_gen_extu_i32_tl(ret, t3); Should this be a signed extend, given it's a signed divide? > } else { > - tcg_gen_movi_i32(t0, 0); > + tcg_gen_setcondi_i32(TCG_COND_EQ, t2, t1, 0); > + tcg_gen_movi_i32(t3, 0); > + tcg_gen_movcond_i32(TCG_COND_NE, t1, t2, t3, t2, t1); > + tcg_gen_divu_i32(t3, t0, t1); > + tcg_gen_extu_i32_tl(ret, t3); > } > if (compute_ov) { > - tcg_gen_movi_tl(cpu_ov, 1); > - tcg_gen_movi_tl(cpu_so, 1); > + tcg_gen_extu_i32_tl(cpu_ov, t2); > + tcg_gen_or_tl(cpu_so, cpu_so, cpu_ov); > } > - gen_set_label(l2); > - tcg_gen_extu_i32_tl(ret, t0); > tcg_temp_free_i32(t0); > tcg_temp_free_i32(t1); > + tcg_temp_free_i32(t2); > + tcg_temp_free_i32(t3); > + > if (unlikely(Rc(ctx->opcode) !=3D 0)) > gen_set_Rc0(ctx, ret); > } --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --B3XPdYri2NuANWBV Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXmERIAAoJEGw4ysog2bOSjH0QAK4U0Yz5PgHJ6gvoa9m6eZvw Y0DAPWS4+vq95Y4+Mj9NC0xbANnsVo6Uf65OnQ5N6rBw1i1KsGnfHe7xoxWECLV5 gc11v3ES+kGIRkRQ0BDMJG7fkqpKtYdAiS0IcZqyoisKdyXL+iL/CEjlZL6iWQLH omVC7ugozQadz3mQlOmAIA5Z71Mo6zMUYOP/PwghKpN1po9desSKZkx27b9v5Nk5 eiMA0efmXrV7MAFt92qjHkQFebNBJVWcneRSxQBrIcvN79z670WriZXe/WFzK4gj AJbxVbOeN6hL2r586wkI329bthUvoyLYll7xtfJfuhjHgedxEPbHzJ+tSPDcR0IH BJYc8v+ZOYobU/A5OOJQkfYJSMhs1uFmSR+T05ljTAQf9vc3YYQioIJsiuo5KU4V 8+UaYVmlCIC4dZ3Y0KatH3+thacW9VZeZlwfKNDKSq3NOqHKjkWgfSflvcNfa2lq 2JmEFHitJl960t26OezDB2uW/5m6T8LmfJSA82Y1XBHJwsWZJuFa2WG2+cHocEoX JH9NY/KxFv2z4mXOZX+HBgaDR0Wf3CWu1eHHXrUBLGK7PhSe6zbeu9EXSDJfNK+d zqphlv2Lo3iZvBQ+z62b4l4huY5ombkdjmhme7kf2bJhXpASigPnLQyA3fjGgpwM dLfAg5lZUQYJa64NrbxU =qhPK -----END PGP SIGNATURE----- --B3XPdYri2NuANWBV--