From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46031) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJ46v-0004XY-6Q for qemu-devel@nongnu.org; Mon, 09 Sep 2013 12:14:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VJ46p-0002wm-L0 for qemu-devel@nongnu.org; Mon, 09 Sep 2013 12:14:45 -0400 Received: from [2a03:4000:1::4e2f:c7ac:d] (port=53801 helo=v220110690675601.yourvserver.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJ46p-0002wX-Dq for qemu-devel@nongnu.org; Mon, 09 Sep 2013 12:14:39 -0400 Message-ID: <522DF3EA.6060606@weilnetz.de> Date: Mon, 09 Sep 2013 18:14:34 +0200 From: Stefan Weil MIME-Version: 1.0 References: <1378327754-8415-1-git-send-email-sw@weilnetz.de> <52279D6A.6040302@weilnetz.de> <20130909145302.GB4966@ohm.aurel32.net> In-Reply-To: <20130909145302.GB4966@ohm.aurel32.net> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] tci: Add implementation of rotl_i64, rotr_i64 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: Richard Henderson , qemu-stable@nongnu.org, qemu-devel Am 09.09.2013 16:53, schrieb Aurelien Jarno: > On Wed, Sep 04, 2013 at 10:51:54PM +0200, Stefan Weil wrote: >> Am 04.09.2013 22:49, schrieb Stefan Weil: >>> It is used by qemu-ppc64 when running Debian's busybox-static. >>> >>> Signed-off-by: Stefan Weil >>> --- >>> >>> This patch is also useful for QEMU 1.6. >> ... so I should have added qemu-stable. Done now. >> > Why is it needed for qemu-stable? It should only improve performance, as > these two ops are not mandatory ops. In general I don't think we should > have performance improvements in a stable minor release (unless of course > it's a big regression from previous). Hi Aurelien, tci has always set TCG_TARGET_HAS_rot_i64, and target-ppc64 uses the rotl_i64 and rotr_i64 TCG opcodes. The old implementation just triggered a TODO assertion. That's how I implemented TCI: I started with TODO assertions for all opcodes and replaced them by real code as soon as I got a test case which used them. Now I have a test case :-) => It's not a performance issue, but fixes a fatal assertion. => It should be used in 1.6. Regards, Stefan