From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43744) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dgGUC-0005UY-KU for qemu-devel@nongnu.org; Fri, 11 Aug 2017 16:24:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dgGU8-0003uN-KN for qemu-devel@nongnu.org; Fri, 11 Aug 2017 16:24:48 -0400 Received: from mail-pg0-x22e.google.com ([2607:f8b0:400e:c05::22e]:33417) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dgGU8-0003tn-BZ for qemu-devel@nongnu.org; Fri, 11 Aug 2017 16:24:44 -0400 Received: by mail-pg0-x22e.google.com with SMTP id u5so19603138pgn.0 for ; Fri, 11 Aug 2017 13:24:44 -0700 (PDT) References: <2fbcf76e4ff63d8527edd3662342948276e2cd37.1502474835.git.alistair.francis@xilinx.com> From: Richard Henderson Message-ID: Date: Fri, 11 Aug 2017 13:24:39 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC v1 3/3] target/arm: Correct exclusive store return value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alistair Francis Cc: "qemu-devel@nongnu.org Developers" , Peter Maydell , Edgar Iglesias , qemu-arm , Edgar Iglesias On 08/11/2017 01:13 PM, Alistair Francis wrote: >>> + tcg_gen_ext_i64(val, val, memop); >> >> What is this addition intended to accomplish? Because of the position within >> the code, you know that memop contains MO_64, so that this is a no-op. > > This is when size == 2 so it's a 32bit operation so memop contains MO_32. It's a paired 32-bit operation, so we're operating on a 64-bit quantity. So extending from 32-bits would be actively wrong. r~