From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7049 invoked by alias); 28 Apr 2011 19:00:31 -0000 Received: (qmail 7036 invoked by uid 22791); 28 Apr 2011 19:00:30 -0000 X-SWARE-Spam-Status: No, hits=-6.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 28 Apr 2011 19:00:09 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p3SJ07qU011849 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 28 Apr 2011 15:00:07 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p3SJ070M008084; Thu, 28 Apr 2011 15:00:07 -0400 Received: from opsy.redhat.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id p3SJ06KT023410; Thu, 28 Apr 2011 15:00:06 -0400 Received: by opsy.redhat.com (Postfix, from userid 500) id 1C572378303; Thu, 28 Apr 2011 13:00:06 -0600 (MDT) From: Tom Tromey To: paawan oza Cc: Petr =?utf-8?Q?Hluz=C3=ADn?= , gdb@sourceware.org, gdb-patches@sourceware.org Subject: Re: [PATCH] arm reversible : References: <341905.10459.qm@web112513.mail.gq1.yahoo.com> <208397.95006.qm@web112517.mail.gq1.yahoo.com> <4DA27006.1080607@codesourcery.com> <763549.92092.qm@web112506.mail.gq1.yahoo.com> <335149.24692.qm@web112515.mail.gq1.yahoo.com> <592215.58786.qm@web112508.mail.gq1.yahoo.com> <172713.29831.qm__351.089161313389$1303740245$gmane$org@web112503.mail.gq1.yahoo.com> <136943.43839.qm@web112518.mail.gq1.yahoo.com> Date: Thu, 28 Apr 2011 19:00:00 -0000 In-Reply-To: <136943.43839.qm@web112518.mail.gq1.yahoo.com> (paawan oza's message of "Thu, 28 Apr 2011 11:26:03 -0700 (PDT)") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-04/txt/msg00548.txt.bz2 >>>>> "Oza" == paawan oza writes: Tom> It seems to me that extract_typed_address or something similar would be Tom> better. Oza> 1) are suggesting to use something else than unions ? whatever you have Oza> described about union is right. Oza> 2) why could I use extract_typed_address instead of direct assignment ? extract_typed_address handles endianess and conversion from "array of bytes" to "host scalar". Oza> 3) in my understanding cross debug would not affect endianess Oza> because all the record saving done on target memory and played back Oza> in target memory. they never get fetched to host machine I think. Oza> please clarify how would it affect host/target endianness issue ? Here is a snippet from the patch: + GET_REG_VAL (reg_cache, ARM_PC_REGNUM, &u_buf.buf[0]); [...] + start_address = u_buf.s_word - \ + (4 * (bit (thumb_insn_r->arm_insn, 8) + register_count)) ; Here, this fetches the raw register bits from the cache, which, IIUC, are in target order. Then it uses the union to turn this into a scalar, and does math on the scalar value. So, if the host and target endianness differ, you will get the wrong result. Maybe I am missing something here? Tom