From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41433) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YwHpV-00054L-7s for qemu-devel@nongnu.org; Sat, 23 May 2015 18:23:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YwHpS-0001JW-2h for qemu-devel@nongnu.org; Sat, 23 May 2015 18:23:41 -0400 Received: from mail-pa0-x22a.google.com ([2607:f8b0:400e:c03::22a]:33472) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YwHpR-0001JS-Ry for qemu-devel@nongnu.org; Sat, 23 May 2015 18:23:38 -0400 Received: by padbw4 with SMTP id bw4so45188784pad.0 for ; Sat, 23 May 2015 15:23:37 -0700 (PDT) Sender: Richard Henderson Message-ID: <5560FD66.4040400@twiddle.net> Date: Sat, 23 May 2015 15:21:26 -0700 From: Richard Henderson MIME-Version: 1.0 References: <636961558.306257.1432383983549.JavaMail.yahoo@mail.yahoo.com> In-Reply-To: <636961558.306257.1432383983549.JavaMail.yahoo@mail.yahoo.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] What's the difference between "ld/st" and "qemu_ld/st" in TCG IR? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?B?5rWp5YCrIOmtjw==?= , "qemu-devel@nongnu.org" On 05/23/2015 05:26 AM, 浩倫 魏 wrote: > So there are some points that I hope you can help me out: > 1. Is every guest load/store instruction would be translated to qemu_ld/st IR? Yes. > 2. What about another TCG IR "ld/st"? What kind of guest instructions would > cause TCG generates that IRs and for what purpose? For instance, vector instructions are often implemented without TCG temporaries, but instead using ld/st to load the data from the ENV pointer directly. You can see that in the ARM and i386 targets. Otherwise, there are sometimes less-used system values that do not warrent a TCG temporary. You can see that in the alpha target. r~