From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MsB1A-0001Jc-If for qemu-devel@nongnu.org; Mon, 28 Sep 2009 03:51:32 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MsB16-0001Gj-5z for qemu-devel@nongnu.org; Mon, 28 Sep 2009 03:51:32 -0400 Received: from [199.232.76.173] (port=37177 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MsB15-0001GX-Rp for qemu-devel@nongnu.org; Mon, 28 Sep 2009 03:51:27 -0400 Received: from mx20.gnu.org ([199.232.41.8]:4523) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MsB15-0005ZB-Br for qemu-devel@nongnu.org; Mon, 28 Sep 2009 03:51:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MsB14-0007gR-GB for qemu-devel@nongnu.org; Mon, 28 Sep 2009 03:51:26 -0400 Message-ID: <4AC06AF0.7010300@redhat.com> Date: Mon, 28 Sep 2009 09:51:12 +0200 From: Avi Kivity MIME-Version: 1.0 References: <200909271613.n8RGDCLo020606@d01av04.pok.ibm.com> In-Reply-To: <200909271613.n8RGDCLo020606@d01av04.pok.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [Qemu-commits] [COMMIT a4b18c6] tcg/x86_64: generated dec/inc instead of sub/addwhen possible List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: "qemu-devel@nongnu.org" On 09/27/2009 06:13 PM, Anthony Liguori wrote: > From: Aurelien Jarno > Intel recommends not using inc/dec. Since these instructions don't update all of the flags, they cannot be issued in parallel to previous instructions that do. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.