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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 B61C8C43331 for ; Fri, 6 Sep 2019 08:00:12 +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 914172070C for ; Fri, 6 Sep 2019 08:00:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 914172070C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53172 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i69AB-0005JG-7y for qemu-devel@archiver.kernel.org; Fri, 06 Sep 2019 04:00:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41995) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i698C-0003T0-Pn for qemu-devel@nongnu.org; Fri, 06 Sep 2019 03:58:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i698B-0002nu-IL for qemu-devel@nongnu.org; Fri, 06 Sep 2019 03:58:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54562) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i698B-0002mM-C0; Fri, 06 Sep 2019 03:58:07 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A31D6307D930; Fri, 6 Sep 2019 07:58:06 +0000 (UTC) Received: from t460s.redhat.com (ovpn-117-162.ams2.redhat.com [10.36.117.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id D26611001B00; Fri, 6 Sep 2019 07:58:04 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Fri, 6 Sep 2019 09:57:27 +0200 Message-Id: <20190906075750.14791-6-david@redhat.com> In-Reply-To: <20190906075750.14791-1-david@redhat.com> References: <20190906075750.14791-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Fri, 06 Sep 2019 07:58:06 +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 v2 05/28] s390x/tcg: 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 , Richard Henderson , Stefano Brivio , qemu-s390x@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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. Reviewed-by: Richard Henderson Signed-off-by: David Hildenbrand --- 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 2e22c183bd..2bc2cd09c1 100644 --- a/target/s390x/mem_helper.c +++ b/target/s390x/mem_helper.c @@ -320,16 +320,20 @@ static uint32_t do_helper_mvc(CPUS390XState *env, u= int32_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 oper= ands + * were processed one byte at a time". Only non-destructive overlaps + * 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