From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dRxLm-00051q-Fa for qemu-devel@nongnu.org; Mon, 03 Jul 2017 05:08:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dRxLj-0003Us-49 for qemu-devel@nongnu.org; Mon, 03 Jul 2017 05:08:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44492) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dRxLi-0003T5-Tg for qemu-devel@nongnu.org; Mon, 03 Jul 2017 05:08:55 -0400 References: <20170622231228.1050-1-david@redhat.com> <20170625221956.rda2cls2ex7icapa@aurel32.net> <98e6dd78-d30d-fdb3-0572-5983154e2669@twiddle.net> From: David Hildenbrand Message-ID: <22333f7b-5e04-7a71-db9b-7f142e21dcd6@redhat.com> Date: Mon, 3 Jul 2017 11:08:49 +0200 MIME-Version: 1.0 In-Reply-To: <98e6dd78-d30d-fdb3-0572-5983154e2669@twiddle.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v1] target-s390x: fix risbg handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , Aurelien Jarno Cc: agraf@suse.de, thuth@redhat.com, qemu-devel@nongnu.org On 01.07.2017 22:27, Richard Henderson wrote: > On 06/25/2017 03:19 PM, Aurelien Jarno wrote: >> On 2017-06-23 01:12, David Hildenbrand wrote: >>> If we have for example: r3 contains 0x00000000ffffffff >>> ec 33 3f bf 61 55 risbg %r3,%r3,63,191,97 >>> >>> We want to rotate 33 to the left and only keep MSB bit 63 of that. So the >>> result is then exactly 1 (we're reading the sign of the 32 bit value). >>> >>> Current code assumes that we can do that via an extract, which is not >>> true (at least not that easy) and produces a 0. >> >> I think the mistake there is that the rotation is done to the left, >> while in extract the "shift" is done to the right. The following patch >> should be enough: >> >> --- a/target/s390x/translate.c >> +++ b/target/s390x/translate.c >> @@ -3441,8 +3441,8 @@ static ExitStatus op_risbg(DisasContext *s, DisasOps *o) >> } >> >> /* In some cases we can implement this with extract. */ >> - if (imask == 0 && pos == 0 && len > 0 && rot + len <= 64) { >> - tcg_gen_extract_i64(o->out, o->in2, rot, len); >> + if (imask == 0 && pos == 0 && len > 0 && rot - len >= 0) { >> + tcg_gen_extract_i64(o->out, o->in2, 64 - rot, len); >> return NO_EXIT; > > Agreed. Included. > > > r~ > Was able to test it with your version and it works just fine! Thanks! -- Thanks, David