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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 3F929C433ED for ; Tue, 13 Apr 2021 07:45:25 +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 B5DBD61019 for ; Tue, 13 Apr 2021 07:45:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5DBD61019 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]:43542 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWDjf-0004Dz-Oy for qemu-devel@archiver.kernel.org; Tue, 13 Apr 2021 03:45:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38802) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWDhS-0002ar-Lp; Tue, 13 Apr 2021 03:43:06 -0400 Received: from ozlabs.org ([203.11.71.1]:37509) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWDhQ-0007rP-AE; Tue, 13 Apr 2021 03:43:06 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4FKHdX10vFz9sVv; Tue, 13 Apr 2021 17:42:56 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1618299776; bh=6imbApBbnoU37MP7z7eiOy0pDcw/QYH7WzR88yrKlp4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jjifVQYFvNDCGPv4dpp0P+mHTkZHXxM/oG5t9wkU+mE++cHRSwRfxKq/s2FhnrT3S TfDnWW2PFrwSqwP/CxzA5INZhvi73p9qtnRWfJKa75BKrqU7c0OaYQkhMbbq/zlfLo nPlrXBWH+eL5eTFDru7quoVsJ6D6q1pGIpJ4xXgA= Date: Tue, 13 Apr 2021 16:42:13 +1000 From: David Gibson To: Richard Henderson Subject: Re: [PATCH 2/4] target/ppc: added solutions for building with disable-tcg Message-ID: References: <20210409151916.97326-1-bruno.larsen@eldorado.org.br> <20210409151916.97326-3-bruno.larsen@eldorado.org.br> <26d5b8e4-693d-f747-3b7f-d984a43f0209@linaro.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="oZw7gLQAITkNJFQA" Content-Disposition: inline In-Reply-To: <26d5b8e4-693d-f747-3b7f-d984a43f0209@linaro.org> Received-SPF: pass client-ip=203.11.71.1; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action 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-devel@nongnu.org, lagarcia@br.ibm.com, lucas.araujo@eldorado.org.br, fernando.valle@eldorado.org.br, qemu-ppc@nongnu.org, andre.silva@eldorado.org.br, "Bruno Larsen \(billionai\)" , matheus.ferst@eldorado.org.br, luis.pires@eldorado.org.br Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --oZw7gLQAITkNJFQA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 12, 2021 at 08:40:47AM -0700, Richard Henderson wrote: > On 4/11/21 10:08 PM, David Gibson wrote: > > Not directly related to what you're trying to accomplish here, but the > > whole vscr_sat thing looks really weird. I have no idea why we're > > splitting out the storage of VSCR[SAT] for the TCG case at all. If > > you wanted to clean that up as a preliminary, I'd be grateful. >=20 > That's about efficiently implementing the vector saturation instructions = in > TCG. See GEN_VXFORM_SAT in translate/vmx-impl.c.inc. >=20 > The SAT bit is represented as a vector that e.g. compares the result of > addition with the result of saturating addition. We don't need to resolve > that to a single bit until the VSCR register is read. Aha, thanks for the input. Long term, that might benefit from KVM specific code paths that don't bother with this then. However, for the first cut, it's simpler to just keep the current representation, even though it's pretty odd for KVM. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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