From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38314) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c7E9J-0001Ya-VI for qemu-devel@nongnu.org; Wed, 16 Nov 2016 23:18:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c7E9I-0002UW-Mu for qemu-devel@nongnu.org; Wed, 16 Nov 2016 23:18:09 -0500 Date: Thu, 17 Nov 2016 14:42:43 +1100 From: David Gibson Message-ID: <20161117034243.GF18808@umbus.fritz.box> References: <1479326850-8369-1-git-send-email-joserz@linux.vnet.ibm.com> <1479326850-8369-2-git-send-email-joserz@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="dWYAkE0V1FpFQHQ3" Content-Disposition: inline In-Reply-To: <1479326850-8369-2-git-send-email-joserz@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 1/4] target-ppc: Implement bcdcfsq. instruction List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jose Ricardo Ziviani Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, nikunj@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com --dWYAkE0V1FpFQHQ3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 16, 2016 at 06:07:27PM -0200, Jose Ricardo Ziviani wrote: > bcdcfsq.: Decimal convert from signed quadword. It is possible to I think there should be a "not" in there. > convert values less than 10^31-1 or greater than -10^31-1 to be > represented in packed decimal format. >=20 > Signed-off-by: Jose Ricardo Ziviani > --- > target-ppc/helper.h | 1 + > target-ppc/int_helper.c | 48 +++++++++++++++++++++++++++++++= ++++++ > target-ppc/translate/vmx-impl.inc.c | 7 ++++++ > 3 files changed, 56 insertions(+) >=20 > diff --git a/target-ppc/helper.h b/target-ppc/helper.h > index da00f0a..87f533c 100644 > --- a/target-ppc/helper.h > +++ b/target-ppc/helper.h > @@ -382,6 +382,7 @@ DEF_HELPER_3(bcdcfn, i32, avr, avr, i32) > DEF_HELPER_3(bcdctn, i32, avr, avr, i32) > DEF_HELPER_3(bcdcfz, i32, avr, avr, i32) > DEF_HELPER_3(bcdctz, i32, avr, avr, i32) > +DEF_HELPER_3(bcdcfsq, i32, avr, avr, i32) > =20 > DEF_HELPER_2(xsadddp, void, env, i32) > DEF_HELPER_2(xssubdp, void, env, i32) > diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c > index 9ac204a..db65a51 100644 > --- a/target-ppc/int_helper.c > +++ b/target-ppc/int_helper.c > @@ -2874,6 +2874,54 @@ uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b,= uint32_t ps) > return cr; > } > =20 > +uint32_t helper_bcdcfsq(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps) > +{ > + int i; > + int cr =3D 0; > + int ox_flag =3D 0; > + uint64_t digit =3D 0; > + uint64_t carry =3D 0; > + uint64_t lo_value =3D 0; > + uint64_t hi_value =3D 0; Most of the variables above don't need initializers. > + uint64_t max =3D ULLONG_MAX; > + ppc_avr_t ret =3D { .u64 =3D { 0, 0 } }; > + > + if (b->s64[HI_IDX] < 0) { > + hi_value =3D -b->s64[HI_IDX]; > + lo_value =3D b->s64[LO_IDX]; I'm pretty sure this is wrong. Take for example 128-bit -1: ffffffff ffffffff ffffffff ffffffff Upper word is negative (64-bit -1), so hi_value =3D 00000000 00000001 lo_value =3D ffffffff ffffffff 0x1 ffffffff ffffffff !=3D +1 > + bcd_put_digit(&ret, 0xD, 0); > + } else if (b->s64[HI_IDX] =3D=3D 0 && b->s64[LO_IDX] < 0) { > + lo_value =3D -b->s64[LO_IDX]; > + bcd_put_digit(&ret, 0xD, 0); > + } else { > + hi_value =3D b->s64[HI_IDX]; > + lo_value =3D b->s64[LO_IDX]; > + bcd_put_digit(&ret, bcd_preferred_sgn(0, ps), 0); > + } > + > + if (unlikely(hi_value > 0x7e37be2022)) { This doesn't look right. Unless by chance 10^31-1 is equal to (k*2^64 - 1) you need to look at the lo_value as well. > + ox_flag =3D 1; You might as well just return 1<< CRF_SO here - no point actually computing a meaningless value. > + } > + > + carry =3D hi_value; > + for (i =3D 0; i < 32; i++, max /=3D 10, lo_value /=3D 10) { Looks like this loop has one too many iterations - there are 32 iterations, but you only have 31 digits. > + digit =3D ((max % 10) * hi_value) + (lo_value % 10) + carry; > + carry =3D (digit > 9) ? digit / 10 : 0; > + > + bcd_put_digit(&ret, (carry) ? digit % 10 : digit, i + 1); Ugh, this is hard to follow. We're already using an Int128 library in the memory region code; wonder if we should just use that here as well. > + } > + > + cr =3D bcd_cmp_zero(&ret); > + > + if (unlikely(ox_flag)) { > + cr |=3D 1 << CRF_SO; > + } > + > + *r =3D ret; > + > + return cr; > +} > + > void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a) > { > int i; > diff --git a/target-ppc/translate/vmx-impl.inc.c b/target-ppc/translate/v= mx-impl.inc.c > index 7143eb3..36141e5 100644 > --- a/target-ppc/translate/vmx-impl.inc.c > +++ b/target-ppc/translate/vmx-impl.inc.c > @@ -989,10 +989,14 @@ GEN_BCD2(bcdcfn) > GEN_BCD2(bcdctn) > GEN_BCD2(bcdcfz) > GEN_BCD2(bcdctz) > +GEN_BCD2(bcdcfsq) > =20 > static void gen_xpnd04_1(DisasContext *ctx) > { > switch (opc4(ctx->opcode)) { > + case 2: > + gen_bcdcfsq(ctx); > + break; > case 4: > gen_bcdctz(ctx); > break; > @@ -1014,6 +1018,9 @@ static void gen_xpnd04_1(DisasContext *ctx) > static void gen_xpnd04_2(DisasContext *ctx) > { > switch (opc4(ctx->opcode)) { > + case 2: > + gen_bcdcfsq(ctx); > + break; > case 4: > gen_bcdctz(ctx); > break; --=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 --dWYAkE0V1FpFQHQ3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJYLScxAAoJEGw4ysog2bOSE+UQAIiZTio9zwHTNhWQVGKQCERB 6Q6HzOQy3EHkvxVQuaOyY7gZqRioUs/QipwMICwi/2i3GVVctKkiLe4C+dpfLZPV /+t2CiuogIT8k6b/cKJD1xY1fiNBVtghGg6LEb/aC08qFrZ+NzFXCBQs9g2f7RUT 2kdXKyxJ1531sNiooXh8w9/ZyL3CppEpytZ0Xv6vzByLbgRx7pChkJr7AS+IsOU5 LgqngFdXFE21792EgybqsJresaTRsj49ZU7zXgMXhEtTDB19yVSWn8FBAYwN4pws 5Hb5k7FUhGLVh531kfCLRbq9lBfxcMYsVgTKhr/dL5xDFkPm/4WtPI3zRr7x2ipv CiBBntf3ZXEYGo18I4U3EkRTKtJInIPhnSETLCNV988LBW6I422iOOz7/EEojcPw ynyVkUYCZdcXXcoA+OGy6Hcpb8BqlC9k9IxceOt8IxH/5AZePhnexCvL8q1Ylb/h ZtOCPTLcfKnaJo+Zio8eAQLx/ialFA9tLriG1hx0ZMcFHZrAXvdSrC5o5Q/Yem5R 9ZWRehOnn1bsJkUgHvuUQmsqLBC6C/W2bWGpngD+ikYpAr+Y4ejYmVdhucMBUZHp 5cxCWF3B/LYtlbllt8c9Ve4XiL8GTn7v9kZld1PAEGDZXJixepGnV7ZICf5iZH2g HqwnypHKg/yWV2M8/Kn9 =oHgL -----END PGP SIGNATURE----- --dWYAkE0V1FpFQHQ3--