From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1550 invoked by alias); 22 Oct 2008 13:37:58 -0000 Received: (qmail 1542 invoked by uid 22791); 22 Oct 2008 13:37:58 -0000 X-Spam-Check-By: sourceware.org Received: from NaN.false.org (HELO nan.false.org) (208.75.86.248) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 22 Oct 2008 13:37:18 +0000 Received: from nan.false.org (localhost [127.0.0.1]) by nan.false.org (Postfix) with ESMTP id D4DF9108C9; Wed, 22 Oct 2008 13:37:16 +0000 (GMT) Received: from caradoc.them.org (209.195.188.212.nauticom.net [209.195.188.212]) by nan.false.org (Postfix) with ESMTP id 84A6C10815; Wed, 22 Oct 2008 13:37:16 +0000 (GMT) Received: from drow by caradoc.them.org with local (Exim 4.69) (envelope-from ) id 1Ksdtk-0002jU-5N; Wed, 22 Oct 2008 09:37:16 -0400 Date: Wed, 22 Oct 2008 13:37:00 -0000 From: Daniel Jacobowitz To: teawater Cc: Jakob Engblom , Michael Snyder , gdb@sourceware.org Subject: Re: [discuss] semantics, "replay debugging" vs. "reverse debugging" Message-ID: <20081022133716.GA10237@caradoc.them.org> Mail-Followup-To: teawater , Jakob Engblom , Michael Snyder , gdb@sourceware.org References: <48FBDA34.6020104@vmware.com> <007e01c9334e$aad56ff0$00804fd0$@com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2008-05-11) X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2008-10/txt/msg00083.txt.bz2 On Wed, Oct 22, 2008 at 11:25:17AM +0800, teawater wrote: > I think your not clear my idea. > > > I think maybe some instruction can do it. > > Such as add instruction. When it forward execute, it add some number > > to a value of register. When it reverse, it can sub this number from > > the value of register. It can reverse without record. > > Maybe you can read this part again. > > And what is the status of program? Most of time, it's just the values > of registers and memory. Do not think anything that complex. Jakob is right. For instance, if the add instruction sets an overflow flag in the status register, you can not figure out what the previous version of the overflow flag was after the instruction. -- Daniel Jacobowitz CodeSourcery