From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60499) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c9j9h-0002YF-IK for qemu-devel@nongnu.org; Wed, 23 Nov 2016 20:48:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c9j9d-0005Ye-NH for qemu-devel@nongnu.org; Wed, 23 Nov 2016 20:48:53 -0500 Date: Thu, 24 Nov 2016 12:29:40 +1100 From: David Gibson Message-ID: <20161124012940.GR17795@umbus.fritz.box> References: <1479815165-31059-1-git-send-email-nikunj@linux.vnet.ibm.com> <1479815165-31059-3-git-send-email-nikunj@linux.vnet.ibm.com> <20161123040118.GK28479@umbus.fritz.box> <20161123054008.GC3550@in.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="wc6dtGz1CZgs+5WP" Content-Disposition: inline In-Reply-To: <20161123054008.GC3550@in.ibm.com> Subject: Re: [Qemu-devel] [PATCH 2/9] target-ppc: Fix xscmpodp and xscmpudp instructions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bharata B Rao Cc: Nikunj A Dadhania , qemu-ppc@nongnu.org, rth@twiddle.net, qemu-devel@nongnu.org --wc6dtGz1CZgs+5WP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 23, 2016 at 11:10:08AM +0530, Bharata B Rao wrote: > On Wed, Nov 23, 2016 at 03:01:18PM +1100, David Gibson wrote: > > On Tue, Nov 22, 2016 at 05:15:58PM +0530, Nikunj A Dadhania wrote: > > > From: Bharata B Rao > > >=20 > > > - xscmpodp & xscmpudp are missing flags reset. > > > - In xscmpodp, VXCC should be set only if VE is 0 for signalling NaN = case > > > and VXCC should be set by explicitly checking for quiet NaN case. > > > - Comparison is being done only if the operands are not NaNs. However= as > > > per ISA, it should be done even when operands are NaNs. > >=20 > > For my interest, can you explain the difference between ordered and > > unordered comparisons? I looked at the ISA and mostly just became > > confused. >=20 > >From another section of the same ISA doc, I see these description which > makes the distinction between ordered and unordered comparisions a bit > more clear. >=20 > Unordered: >=20 > "If either of the operands is a NaN, either quiet or signal- > ing, then CR field BF and the FPCC are set to reflect > unordered. If either of the operands is a Signaling NaN, > then VXSNAN is set." >=20 > Ordered: >=20 > "If either of the operands is a NaN, either quiet or signal- > ing, then CR field BF and the FPCC are set to reflect > unordered. If either of the operands is a Signaling NaN, > then VXSNAN is set and, if Invalid Operation is dis- > abled (VE=3D0), VXVC is set. If neither operand is a Sig- > naling NaN but at least one operand is a Quiet NaN, > then VXVC is set." Ah, thanks. So it's basically just the setting of VXVC which differs. --=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 --wc6dtGz1CZgs+5WP Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJYNkKEAAoJEGw4ysog2bOShiAP/0gNxq0w0kaZWq4H1d9kFY6N SIEZXmArZDRZU8CeXY2744EraLh0kC4pEmySTrZZYVSuiLCfP9Su9rsyBXeryfuc aY7iK5+gACb0akBtNfrErDWit815IVo9Yi9oKIqqsLI9MBN5ioyV1whnqJpn0Z1V aWD0fr+9Q5/HHv79aDGpu9JxQCw5s6eQ57hjqfptU+gPEL0nSdpV80rCsNILOjol DOd5ZlyWQ4BOZmjTptJ2FF6mpjX6QcfTSIQEWkkTj3MRRRqIn8UUIzu+vnVKlZg/ wPdo1e4dCoPhEjoEZZ8+rSSPMDNdqKtaKtia4tnMrLWD1yHE4gIDWESFys/t0RKX DvDjznY9Np3yUitVvneQA9GfGksFAju5SspgYsTvKx7g6zQpLD66KbcwjFqXZgt3 rMOoHYnD9sQRQ9FN9aspwf3paaQpC9WiXIp2iVWcTy2sljforuXw3Uz4B+Ezu/Tf 9+D/h+oe/vA165yt80oiwMUQ3GRgv6cf+tIstnidibDdU3c+d0V14WIu4O3OP0ms eiIeFQ2MrcN5c3KsyT++ghb3NL7o5sHrqrbMrDHmiCOS3Ku9quezdGMCcg6i5LfI oc/kPurNieUdz5D6TPOTTAoOkjrTQ3Avus1qTMSo3xeeT0aRn199KUKcAOYj+LKm TAluCpQ8QGYFnuIakcrQ =ujPd -----END PGP SIGNATURE----- --wc6dtGz1CZgs+5WP--