From patchwork Thu Sep 19 12:40:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cornelia Huck X-Patchwork-Id: 11152365 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 63F1576 for ; Thu, 19 Sep 2019 13:20:31 +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 43E5021924 for ; Thu, 19 Sep 2019 13:20:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43E5021924 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:43884 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAwMH-0004T8-OY for patchwork-qemu-devel@patchwork.kernel.org; Thu, 19 Sep 2019 09:20:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41649) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAvsf-0006je-PZ for qemu-devel@nongnu.org; Thu, 19 Sep 2019 08:49:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAvkk-0008CD-C1 for qemu-devel@nongnu.org; Thu, 19 Sep 2019 08:41:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45406) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAvkk-0008Ax-3c; Thu, 19 Sep 2019 08:41:42 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 61CEE307D923; Thu, 19 Sep 2019 12:41:41 +0000 (UTC) Received: from localhost (dhcp-192-230.str.redhat.com [10.33.192.230]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A4C045D6B2; Thu, 19 Sep 2019 12:41:36 +0000 (UTC) From: Cornelia Huck To: Peter Maydell Date: Thu, 19 Sep 2019 14:40:46 +0200 Message-Id: <20190919124115.11510-6-cohuck@redhat.com> In-Reply-To: <20190919124115.11510-1-cohuck@redhat.com> References: <20190919124115.11510-1-cohuck@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Thu, 19 Sep 2019 12:41:41 +0000 (UTC) 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] [PULL 05/34] 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: qemu-s390x@nongnu.org, Richard Henderson , qemu-devel@nongnu.org, David Hildenbrand Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: David Hildenbrand 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 58ab2e48e341..013e8d6045e7 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, uint32_t l, uint64_t dest, HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n", __func__, l, dest, src); - /* 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 operands + * were processed one byte at a time". Only non-destructive overlaps + * behave like memmove(). + */ if (dest == 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 <= dest) { + fast_memmove(env, dest, src, l, ra); } else { - /* slow version with byte accesses which always work */ - for (i = 0; i <= l; i++) { + for (i = 0; i < l; i++) { uint8_t x = cpu_ldub_data_ra(env, src + i, ra); cpu_stb_data_ra(env, dest + i, x, ra); }