From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755277Ab0IJBxM (ORCPT ); Thu, 9 Sep 2010 21:53:12 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:58923 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754103Ab0IJBxK (ORCPT ); Thu, 9 Sep 2010 21:53:10 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:x-mailer:mime-version:content-type :content-transfer-encoding; b=t1oMV+23ZrKI9mDXs3FTIhpT0dlAF/xhs6mbNOKgymA7B50f/H3+91qA3vqDvyAgYO w4refUwoecwoLKHik5Yaiw5GqbvASZMYKc6r7DfkoZ5UM/0hDExbXy4HZZug43VkR3Zz 6DD/drrrhtcfBOky+4Vpw+zuMwPFBHJmSOheU= Date: Fri, 10 Sep 2010 09:53:10 +0800 From: "hacklu" To: "linux-kernel" Subject: how to understand powerpc's BRx ORx Message-ID: <201009100953083354338@gmail.com> X-mailer: Foxmail 6, 15, 201, 22 [cn] Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I didn't understand the address mask. it's said that: BR[BA] is the base address,the OR[AM] is the address mask, "Provides masking for corresponding BRx bits. By masking address bits independently, SDRAM devices of different size address ranges can be used. Clearing bits masks the corresponding address bit. Setting bits causes the corresponding address bit to be compared with the address pins. Address mask bits can be set or cleared in any order, allowing a resource to reside in more than one area of the address map. SDAM can be read or written at any time." how to understand it? for instance, if my BR0[BA]=0111_0000_0000_0000_0, OR0[AM]=1111_1111_1111 if I want to access the 0x70000000 or the 0x71000001.what address calculate will be taken? thanks all -------------- hacklu 2010-09-10