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=-5.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BB5D7C35254 for ; Mon, 17 Feb 2020 09:52:09 +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 86C47206F4 for ; Mon, 17 Feb 2020 09:52:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="wjppmEY8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 86C47206F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42834 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3d4S-0003NU-PP for qemu-devel@archiver.kernel.org; Mon, 17 Feb 2020 04:52:08 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55309) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3d3e-0002mo-DC for qemu-devel@nongnu.org; Mon, 17 Feb 2020 04:51:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j3d3c-0006tt-Vy for qemu-devel@nongnu.org; Mon, 17 Feb 2020 04:51:17 -0500 Received: from mail-ot1-x342.google.com ([2607:f8b0:4864:20::342]:46015) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1j3d3c-0006r8-Lh for qemu-devel@nongnu.org; Mon, 17 Feb 2020 04:51:16 -0500 Received: by mail-ot1-x342.google.com with SMTP id 59so15488270otp.12 for ; Mon, 17 Feb 2020 01:51:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=eIj3pcX+cu38WlJqrjU9icvt5rk8G461KC2HqJqYeUQ=; b=wjppmEY8fO4qlqW5SesLwykAsqMJGN4iiYA3vVjFyH19/rOHPYZ/b6P98lNRW2Jftl 8zteog06c2cfSSDsFJ34Q1H0KNkpLxbl3GLXaKuO0q9Lrz693P/p0OaSuCwh/kmR5UtU NqJYhnLIxDF8jebh+0VqSo82GasJ5h6faYgLFGVQk36EOOkxMlmUx6ws70C0YfcJ+TKE qiEyTCsRSn8ahLZG/5wPkDjkq/lb6M0VQq19ziWuAeZeXX6nL8gBWaF+8IFMEUwqRmnF Oo3dkie+OIwbEziluZZg3KBcmSeVNdtSgRLa9i/3AbbhyAekLdLItTO5PGWGat8Br3UF WhxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=eIj3pcX+cu38WlJqrjU9icvt5rk8G461KC2HqJqYeUQ=; b=SYM5Sa77F6p5zvrtWZLn55lt38z2xFLH0lqI0SP9+1qgltemxe/D0IHdK6NPMJuLri dyZ4rsiRD+Ty+w4KZRn3QxIjKXKJIAMwiBAcvpy0rAfivPKeXXxMzu6UmhX2WIdPjh89 InG0SJ4H6TehENtJCqn4z7wO8Ch5l+dG2UyuISCfxsKo+tZGqSP98qGMqut+qVsB/Pc8 eWRczWcuT8VoTQy2VG9LCpgn03aZ0q57zCWg+lfAND/9eLqSUT7C0e1IcmimYGv+/yQz lFoaWJuEW5JKqDQa471QGOQghaAs/ufR1/5CLWH1TjRfDf0taQ3ChRyxRYrdhFjGnuOF B2cQ== X-Gm-Message-State: APjAAAW2Y7m6boajT6fvTDjUOAm/IDkEVPpH96d5lZ509SiPlykilBuA GhFKylxDAm2QYscNKJK3TNXT1u4lDZQBD9zCth2npw== X-Google-Smtp-Source: APXvYqwjynN2Zdzqe5f4HwZrEobUG2HbagjiAi1WbQn3Q33BR1A2PM0a5Z40PuhqRtcg1dO0l4P3w8R1oznCU1Y4Gj8= X-Received: by 2002:a05:6830:13da:: with SMTP id e26mr10787927otq.97.1581933075601; Mon, 17 Feb 2020 01:51:15 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Peter Maydell Date: Mon, 17 Feb 2020 09:51:04 +0000 Message-ID: Subject: Re: [RFC PATCH 0/2] Enable hardfloat for PPC To: BALATON Zoltan Content-Type: text/plain; charset="UTF-8" X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::342 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: Mark Cave-Ayland , QEMU Developers , John Arbuckle , qemu-ppc , Paul Clarke , Howard Spoelstra , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 17 Feb 2020 at 02:43, BALATON Zoltan wrote: > > Hello, > > This is an RFC series to start exploring the possibility of enabling > hardfloat for PPC target that haven't progressed in the last two years. > Hopefully we can work out something now. Previously I've explored this > here: > > https://lists.nongnu.org/archive/html/qemu-ppc/2018-07/msg00261.html > > where some ad-hoc benchmarks using lame mp3 encoder is also explained > that has two versions: one using VMX and another only using FP. Both > are mostly floating point bounded. I've run this test on mac99 under > MorphOS before and after my patches, also verifying that md5sum of > resulting mp3 matches (this is no proof for correctness but maybe > shows it did not break too much at least those ops used by this > program). > I hope others can contribute to this by doing more testing to find out > what else this would break or give some ideas how this could be > improved. I think the ideal would be to test against a reference using risu to see whether this changes behaviour (FP results should be bit-for-bit identical; usually application level testing is often not sufficient to detect this). You could test either against real hardware or against the non-hardfloat QEMU. I'm not sure how comprehensive the coverage for ppc insns is but there are a fair number of fp insns covered already: https://git.linaro.org/people/peter.maydell/risu.git/tree/ It's also worth testing any alternate/non-standard config modes the FPU might have (eg different default rounding modes, any flush-to-zero or alternate denormal handling, that kind of thing), and not just the default how-the-CPU-boots-up mode. thanks -- PMM