From nobody Sun Feb 8 12:19:43 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1566379502; cv=none; d=zoho.com; s=zohoarc; b=EM2UcF0/3fxBWb6xwPLE5r3vwORK1PRZoFeiZsfIjbVmxzF1QmtcNzTYBz3yoFYI9t4mLKi4jgiZqa3KB1qz0/KDefcN12P4gXahOk/UEQKEIW0E/Foj8Ihsi15GWmmAhs2iUxQhMK7h7o/+o2dlKWNNwQqk6R1YKodq7rskZws= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1566379502; h=Content-Transfer-Encoding:Cc: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:ARC-Authentication-Results; bh=mMoEXZBe2c85RpC+di4S3/83oiqTCiWfUw9wWmyBJmc=; b=lz4Mohj4mLvNAxQiTvUQCcW1Wn0wy9iI0e8Cac9qsPpz2AZaZk+vVmAQ8wU9uMuEsGS/TihoUykecln9UX/E3ff9tJChbrKxDCoKmCMTrEBLSFVJdPmbefKP6xXYhAQcZWeo0BV2QO3lPqDE6i99iOEc+412Mppxc92zNakP5xk= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1566379502003419.23749753706556; Wed, 21 Aug 2019 02:25:02 -0700 (PDT) Received: from localhost ([::1]:46390 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i0MrU-00008o-Qw for importer@patchew.org; Wed, 21 Aug 2019 05:25:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36883) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i0Mpd-0006GR-Ie for qemu-devel@nongnu.org; Wed, 21 Aug 2019 05:23:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i0Mpc-0001Cn-Gh for qemu-devel@nongnu.org; Wed, 21 Aug 2019 05:23:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57198) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i0Mpc-0001CO-B3; Wed, 21 Aug 2019 05:23:04 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9BEDE307D88D; Wed, 21 Aug 2019 09:23:03 +0000 (UTC) Received: from t460s.redhat.com (unknown [10.36.118.29]) by smtp.corp.redhat.com (Postfix) with ESMTP id F0FC05C890; Wed, 21 Aug 2019 09:23:01 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Wed, 21 Aug 2019 11:22:51 +0200 Message-Id: <20190821092252.26541-4-david@redhat.com> In-Reply-To: <20190821092252.26541-1-david@redhat.com> References: <20190821092252.26541-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Wed, 21 Aug 2019 09:23:03 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v1 3/4] s390x/tcg: MOVE (MVC): Increment the length once 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: Florian Weimer , Thomas Huth , David Hildenbrand , Cornelia Huck , Stefano Brivio , qemu-s390x@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" Let's increment the length once. While at it, cleanup the comment. The memset() example is given as a programming note in the PoP, so drop the description. Signed-off-by: David Hildenbrand Reviewed-by: Richard Henderson --- target/s390x/mem_helper.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c index 4e9d126e2c..bf7dfcdc7a 100644 --- a/target/s390x/mem_helper.c +++ b/target/s390x/mem_helper.c @@ -307,16 +307,20 @@ static uint32_t do_helper_mvc(CPUS390XState *env, uin= t32_t l, uint64_t dest, HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n", __func__, l, dest, src); =20 - /* mvc and memmove do not behave the same when areas overlap! */ - /* mvc with source pointing to the byte after the destination is the - same as memset with the first source byte */ + /* MVC always copies one more byte than specified - maximum is 256 */ + l++; + + /* + * "When the operands overlap, the result is obtained as if the operan= ds + * were processed one byte at a time". Only non-overlapping or forward + * moves behave like memmove(). + */ if (dest =3D=3D src + 1) { - fast_memset(env, dest, cpu_ldub_data_ra(env, src, ra), l + 1, ra); - } else if (dest < src || src + l < dest) { - fast_memmove(env, dest, src, l + 1, ra); + fast_memset(env, dest, cpu_ldub_data_ra(env, src, ra), l, ra); + } else if (dest < src || src + l <=3D dest) { + fast_memmove(env, dest, src, l, ra); } else { - /* slow version with byte accesses which always work */ - for (i =3D 0; i <=3D l; i++) { + for (i =3D 0; i < l; i++) { uint8_t x =3D cpu_ldub_data_ra(env, src + i, ra); cpu_stb_data_ra(env, dest + i, x, ra); } --=20 2.21.0