From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47C49C31E46 for ; Wed, 12 Jun 2019 05:27:56 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 18D3D206E0 for ; Wed, 12 Jun 2019 05:27:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="pEa6k2nS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18D3D206E0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56760 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1havnf-0007ai-DS for qemu-devel@archiver.kernel.org; Wed, 12 Jun 2019 01:27:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55149) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1havl5-0005Sc-D3 for qemu-devel@nongnu.org; Wed, 12 Jun 2019 01:25:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1havl4-0007i1-70 for qemu-devel@nongnu.org; Wed, 12 Jun 2019 01:25:15 -0400 Received: from ozlabs.org ([2401:3900:2:1::2]:46459) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1havl3-0007h9-PL; Wed, 12 Jun 2019 01:25:14 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 45NwL52J15z9s9y; Wed, 12 Jun 2019 15:25:01 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1560317101; bh=7VICz6MrWLn1BeiBV66AE/FzaL2PZkA/wKzIxPWcWBs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pEa6k2nStoF+f6xaF1Hn5BrtRNONQNPdi+bDXvKeHY38v85QgxDvR+nxxs5NiOhUR emluPQckyg3GK/LSG+rY2XTUVMXbeMjc5aTzatcYsgVJKDIltjGTaP5/RzavZ294qJ y8h04OeQDWdJLrz/rVJMXdq1ZEJhiImHHV9wqwRQ= Date: Wed, 12 Jun 2019 15:16:05 +1000 From: David Gibson To: Richard Henderson Message-ID: <20190612051604.GI3998@umbus.fritz.box> References: <20190602110903.3431-1-mark.cave-ayland@ilande.co.uk> <20190602110903.3431-5-mark.cave-ayland@ilande.co.uk> <20190612015224.GG3998@umbus.fritz.box> <53c86ca8-332c-e073-0e78-2a684cd05161@twiddle.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="G3juXO9GfR42w+sw" Content-Disposition: inline In-Reply-To: <53c86ca8-332c-e073-0e78-2a684cd05161@twiddle.net> User-Agent: Mutt/1.11.4 (2019-03-13) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2401:3900:2:1::2 Subject: Re: [Qemu-devel] [PATCH v2 04/15] target/ppc: introduce separate VSX_CMP macro for xvcmp* instructions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, gkurz@kaod.org, Mark Cave-Ayland , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --G3juXO9GfR42w+sw Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 11, 2019 at 09:22:15PM -0700, Richard Henderson wrote: > On 6/11/19 6:52 PM, David Gibson wrote: > > On Sun, Jun 02, 2019 at 12:08:52PM +0100, Mark Cave-Ayland wrote: > >> Rather than perform the VSR register decoding within the helper itself, > >> introduce a new VSX_CMP macro which performs the decode based upon xT,= xA > >> and xB at translation time. > >> > >> Subsequent commits will make the same changes for other instructions h= owever > >> the xvcmp* instructions are different in that they return a set of fla= gs to be > >> optionally written back to the crf[6] register. Move this logic from t= he > >> helper function to the generator function, along with the > >> float_status update. > >=20 > > What's the advantage of this. Since we still have a helper, don't we > > suffer the cost of the helper call *plus* the now-generated > > instructions? >=20 > Not as such. >=20 > The generated instructions are all of the form >=20 > lea offset+x*16(env), reg >=20 > which is cheaper than >=20 > mov $x, reg >=20 > and then >=20 > shl $4, reg > lea offset(env, reg), reg >=20 > within the helper. Fair enough. Richard, I was kind of hoping for an A-b or R-b on the series from you, but didn't see one..? --=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 --G3juXO9GfR42w+sw Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAl0AipQACgkQbDjKyiDZ s5LAgQ//a1vmDtwGPiZAQpUaqn27w33oPotdvLI06bnQyrU5HcFqvNprAAfD3lnv LJnND3E30iTMx21mt1qbFUjRiYcgjPzrQwnuI846nRaj2jqP296O5R8i1YpwG7u8 fPfjBWtCir+tF6abyRLlaDHoUGIV2c6OghcukdAQwA8IIkFXJGoCeBQIXtSSXDaj vQfw9VKFiCFXuVNUHBJnWvCz55Bpbatyy/X2XPA7xsNi0ZYM3eX+Evbz4ojtRrRi H4vs1kPQEp/An5+5t326cELQacIY3uJu3YdFO+6qCA9jzjKh2MnEhnjbkbIFh5+d e5YRtEkwLKxCZ6x0pSFyCshIjk3BkSyc0FqvUvWIRJ4iFOfiL2OXQwbSVkX7HsYM Xawp1IzVCHc2bAqwFyRbxV099YcfRRXaMFlPZRC9uKQOS4CS7StGOusar+G3oM2A Rt8d2OIkuxSVDWzLYxLLLG32dB0DfRJUIf4haHuhhIGCdCet8dhVih0nDxOY2I80 y9MC45nPEnpiCL5h4/a2L4C8N+TJlZqz/IiQIeb00A2pC5Gv61XnyaaKHPGjX2D7 8Ddsa3f7yd1NuErbTCuZzCEvRXMCCw06DG3DRum/9rASsV9kO1rpWg8vCfqGgO+M SdQHZdyQHmOWtZkB+8BP1au5402y/YM2DzF71KjmN13ZMaOyPKQ= =2YxY -----END PGP SIGNATURE----- --G3juXO9GfR42w+sw--