From nobody Tue Feb 10 10:54:55 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1627558155; cv=none; d=zohomail.com; s=zohoarc; b=bovoUyq7q9/BR7bbKP0zDY2CVOsH+NlgJedq9bSh9gOd1udmuvuPDe5yewE5XJtMUJHJlab5Gp+JQA9beYFl7JjZknFltAev1jvIC9k/G2AVI5WhJXOzPxSKIEaOK0OVLV6a6mRcykjGXiYr312Yj+RDH/VxaSJLUj73F4v2WYo= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1627558155; h=Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=KHg6Srrabt2i/P1wMabf21oSUvedE7e5kSg7WXSq3yY=; b=eMLNyjiHIhtBCbmlHN5uL8y0rSFF1QAqjD9JO+itrv0QkcLIQOfgNJYaaGFq/HQcqVUaGhvR7s6v8ahUHrOyqydfKEkJiMlWB0pdVqyBXq0P3zEvRCWVWPYvdbCQK6UX88DRGS5sEYyP+mM8GRK9qPtUbe7CUwjoLUCD+Ph+Sx8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 162755815595182.97319279588521; Thu, 29 Jul 2021 04:29:15 -0700 (PDT) Received: from localhost ([::1]:60442 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m94Dx-0003SR-SJ for importer@patchew.org; Thu, 29 Jul 2021 07:29:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39860) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m940k-0000QI-0q for qemu-devel@nongnu.org; Thu, 29 Jul 2021 07:15:37 -0400 Received: from mail-wr1-x42f.google.com ([2a00:1450:4864:20::42f]:47095) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1m940a-00010B-5f for qemu-devel@nongnu.org; Thu, 29 Jul 2021 07:15:33 -0400 Received: by mail-wr1-x42f.google.com with SMTP id c16so6427554wrp.13 for ; Thu, 29 Jul 2021 04:15:21 -0700 (PDT) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id j140sm3037829wmj.37.2021.07.29.04.15.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 04:15:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=KHg6Srrabt2i/P1wMabf21oSUvedE7e5kSg7WXSq3yY=; b=dzA/zddL6DXQVfgUPv4PH0cqozt2cdld1eme+ZTUV6sOfT+OLDJVEaCgSDY+FzSnxR BZsgX8GOUHy0eeDz8G/vStNLHH17b9AZhuPrljAAEAIg6sCuyYmB+oVzr/YjWL+VHjOB 124p6XzEe0lc71UAEknrAQN1I5r0UzKSMAWQ+Z2p6WoxCJ08U5wRHUDE6SmKOoXJ7OGN nrmzxz1fYHRorntH3bomR17oui9sPG7AGTYm7wJYFc00tnyzN3euiwu6/lLsHlayApsh lnSoFGzrhL8MAXOjRd5h6GzFk4GJl5YbfhVdGI5HHVSbHf/cBTZEjGACK2LXSdW4qew5 9vyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KHg6Srrabt2i/P1wMabf21oSUvedE7e5kSg7WXSq3yY=; b=m+vEYZw+XxX3gtsf5yd6qnzSr3mioPnBZgWyavqtmf5UrQDLsZY8OvKVZqR21godO2 SwlYL4rWfkSB1Y1j9ZUkRA/Q91Y009tvK+LO6dVckannyUC9bVM2uOQJ0oDayOMMzcdw xpbWXsXWcEUt5NFPFQ3Zfefv2470ivp1JihrhDI8Cc28Qgy3bYU/7CqvaRU3TLIokFOz /+NVVsyaHMszEi0iz+rggyEV3eJZYKGNOAMTx/p9NRzSWMVWPG5bAkeG0rn9GenphF8/ 940XHvCJutlRNY/iZKKrmLBTQMZQ1QJx1V3/jpUptXAgA02Y1AN+6glSrlLb5/o2H6rk WoBQ== X-Gm-Message-State: AOAM5312Hm0XArDffjw4oleMJPQeG6TkjNITpwpuCedeVtHhhSyJ9sI1 FxSK1fvSLnxUEgqbzq0DSKeI5w== X-Google-Smtp-Source: ABdhPJx9IRd7dXOldI4aiu1IO/1iEsQAd7scPCTDBCk09B1b25Lzv98SnpvRQyY0cJd/X6unryuITA== X-Received: by 2002:a5d:5412:: with SMTP id g18mr4320538wrv.301.1627557320596; Thu, 29 Jul 2021 04:15:20 -0700 (PDT) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH for-6.2 07/53] target/arm: Fix MVE 48-bit SQRSHRL for small right shifts Date: Thu, 29 Jul 2021 12:14:26 +0100 Message-Id: <20210729111512.16541-8-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210729111512.16541-1-peter.maydell@linaro.org> References: <20210729111512.16541-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::42f; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x42f.google.com 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, 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1627558156698100001 Content-Type: text/plain; charset="utf-8" We got an edge case wrong in the 48-bit SQRSHRL implementation: if the shift is to the right, although it always makes the result smaller than the input value it might not be within the 48-bit range the result is supposed to be if the input had some bits in [63..48] set and the shift didn't bring all of those within the [47..0] range. Handle this similarly to the way we already do for this case in do_uqrshl48_d(): extend the calculated result from 48 bits, and return that if not saturating or if it doesn't change the result; otherwise fall through to return a saturated value. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- Not squashed into the previous patch because that one has already been reviewed, so as this fixes a different edge case I thought it clearer kept separate. --- target/arm/mve_helper.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c index 5730b48f35e..1a4b2ef8075 100644 --- a/target/arm/mve_helper.c +++ b/target/arm/mve_helper.c @@ -1563,6 +1563,8 @@ uint64_t HELPER(mve_uqrshll)(CPUARMState *env, uint64= _t n, uint32_t shift) static inline int64_t do_sqrshl48_d(int64_t src, int64_t shift, bool round, uint32_t *sat) { + int64_t val, extval; + if (shift <=3D -48) { /* Rounding the sign bit always produces 0. */ if (round) { @@ -1572,9 +1574,14 @@ static inline int64_t do_sqrshl48_d(int64_t src, int= 64_t shift, } else if (shift < 0) { if (round) { src >>=3D -shift - 1; - return (src >> 1) + (src & 1); + val =3D (src >> 1) + (src & 1); + } else { + val =3D src >> -shift; + } + extval =3D sextract64(val, 0, 48); + if (!sat || val =3D=3D extval) { + return extval; } - return src >> -shift; } else if (shift < 48) { int64_t extval =3D sextract64(src << shift, 0, 48); if (!sat || src =3D=3D (extval >> shift)) { --=20 2.20.1