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=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 C01E1C433E7 for ; Mon, 19 Oct 2020 16:13:15 +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 4075F2225F for ; Mon, 19 Oct 2020 16:13:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="gaxKbqXC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4075F2225F 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]:33820 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kUXmc-0002TX-5Y for qemu-devel@archiver.kernel.org; Mon, 19 Oct 2020 12:13:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53412) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kUXaY-0007Fs-VY for qemu-devel@nongnu.org; Mon, 19 Oct 2020 12:00:48 -0400 Received: from mail-pf1-x442.google.com ([2607:f8b0:4864:20::442]:45659) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kUXaW-0000uR-T5 for qemu-devel@nongnu.org; Mon, 19 Oct 2020 12:00:46 -0400 Received: by mail-pf1-x442.google.com with SMTP id e7so178938pfn.12 for ; Mon, 19 Oct 2020 09:00:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=ktXfc0M6AXq8Oo1fufQofEfLrkP7OroL2DgAT7LcHV4=; b=gaxKbqXCJW1mw3gDPnCKTc7tv1dUW9f/fD/v25O0MEl37CR7Dz5IrA4gVBtrdo7Szk IvaN3kH5xRWu34UWwq0Pa1HA8zSFYuuawQWRoLXPYF6WoVFK0VcnDUchAKIlGs4EmgTI bGAAMJRwfvvGy8Nk2I4uinlxRvLMhiu5+nSyhKlAAf02++3MJzE2gi/2MOKE0Cg7CH16 N5WNeu3w12I/nJ4nTXHXKEv/Q50F2+2YGU2kHJNPHYUW2/kWQbKe657hM/UtFqVSswn7 i9Z+LrCc/5BB3u9r/Z40jef7Di9m02Ij8nXb5TILyflNRt+t5zcXqlcj6hwzpqbAojoH wWmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ktXfc0M6AXq8Oo1fufQofEfLrkP7OroL2DgAT7LcHV4=; b=I6kvjit+9eJ688H/elpcjZ6kYaVIpMEIcq8MTXUy6ouFmwdXzZqhbMollzHKdZvs/T +qhROnB3VQLne+wTKlkYXboSS8Df+X01HCGYZfj7ey1fYHahe/gPRUHHGcS8074EHaCs 7j9nAYkt5aX728S2XbtDmJ/hsGLW7GWPRj0CVJThtFWNiespPDccgdIZcTUKNLDGxrcD hVmoDaD+aMyXd0FvGb1YPvLomXoH/0aUrNmIaYZ/p2Jphg0SpLW9Ng6Sevjf+AEX4lzQ s8vqg994ycrWpXiKKOUerqqsf3nom3MGamhOM3IftRlWXz9phlKiN0rqNyJ5UxoPnDWR gc7Q== X-Gm-Message-State: AOAM532CNQDyRYFg7qRv7MWcqLVJbEYM5Yw8YMAqKHWFSlRsEk7upknA UPthkkn9zzaIlmblIh9dWtmDs+bdEolv1A== X-Google-Smtp-Source: ABdhPJyB6GRx3EFtKo6Hq6g9fmWgrr17NB5EBa6YDhe9QE80BiciYIM5gfKeduQz/1DnH7GaKOpEwA== X-Received: by 2002:aa7:9811:0:b029:15d:2c0e:e947 with SMTP id e17-20020aa798110000b029015d2c0ee947mr252949pfl.76.1603123242529; Mon, 19 Oct 2020 09:00:42 -0700 (PDT) Received: from [192.168.1.11] ([71.212.141.89]) by smtp.gmail.com with ESMTPSA id ng7sm21534pjb.14.2020.10.19.09.00.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Oct 2020 09:00:41 -0700 (PDT) Subject: Re: [PATCH v2 10/10] target/arm: Implement FPSCR.LTPSIZE for M-profile LOB extension To: Peter Maydell , qemu-arm@nongnu.org, qemu-devel@nongnu.org References: <20201019151301.2046-1-peter.maydell@linaro.org> <20201019151301.2046-11-peter.maydell@linaro.org> From: Richard Henderson Message-ID: <699b310b-8164-1c20-e858-ffa4d838318d@linaro.org> Date: Mon, 19 Oct 2020 09:00:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201019151301.2046-11-peter.maydell@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::442; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x442.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/19/20 8:13 AM, Peter Maydell wrote: > If the M-profile low-overhead-branch extension is implemented, FPSCR > bits [18:16] are a new field LTPSIZE. If MVE is not implemented > (currently always true for us) then this field always reads as 4 and > ignores writes. > > These bits used to be the vector-length field for the old > short-vector extension, so we need to take care that they are not > misinterpreted as setting vec_len. We do this with a rearrangement > of the vfp_set_fpscr() code that deals with vec_len, vec_stride > and also the QC bit; this obviates the need for the M-profile > only masking step that we used to have at the start of the function. > > We provide a new field in CPUState for LTPSIZE, even though this > will always be 4, in preparation for MVE, so we don't have to > come back later and split it out of the vfp.xregs[FPSCR] value. > (This state struct field will be saved and restored as part of > the FPSCR value via the vmstate_fpscr in machine.c.) > > Signed-off-by: Peter Maydell > --- > target/arm/cpu.h | 1 + > target/arm/cpu.c | 9 +++++++++ > target/arm/vfp_helper.c | 6 ++++++ > 3 files changed, 16 insertions(+) Reviewed-by: Richard Henderson r~