From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48570) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiL4l-0003p5-Rw for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:06:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aiL4h-0002Kh-SR for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:06:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53159) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiL4h-0002KE-Nx for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:06:15 -0400 Date: Tue, 22 Mar 2016 12:06:11 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20160322120611.GD2216@work-vm> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] About PC_COMPAT List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?utf-8?B?5L2Y5pe7?= Cc: qemu-devel * =E4=BD=98=E6=97=BB (chagg@foxmail.com) wrote: > I find PC_COMPAT_X_Y macros in file pc.h, and I don't understand why th= e smaller is the X_Y the more the devices defined? Can someone explain? T= hanks! It's because they're the difference from the current version - so the old= er the version the more differences. So PC_COMPAT_2_5 has no differences, PC_COMPAT_2_4 is 2_5's differences (= none) plus a handful of CPU differences. The PC_COMPAT_2_3 is PC_COMPAT_2_4's = differences plus a bunch of differences that went in between 2.3 and 2.4. Dave -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK