From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23993 invoked by alias); 17 Oct 2008 19:49:45 -0000 Received: (qmail 23984 invoked by uid 22791); 17 Oct 2008 19:49:45 -0000 X-Spam-Check-By: sourceware.org Received: from smtp-outbound-2.vmware.com (HELO smtp-outbound-2.vmware.com) (65.115.85.73) by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 17 Oct 2008 19:49:09 +0000 Received: from mailhost2.vmware.com (mailhost2.vmware.com [10.16.67.167]) by smtp-outbound-2.vmware.com (Postfix) with ESMTP id 04DDF4A007; Fri, 17 Oct 2008 12:49:08 -0700 (PDT) Received: from [10.20.92.59] (promb-2s-dhcp59.eng.vmware.com [10.20.92.59]) by mailhost2.vmware.com (Postfix) with ESMTP id EF8D88E578; Fri, 17 Oct 2008 12:49:07 -0700 (PDT) Message-ID: <48F8EB4F.1070904@vmware.com> Date: Fri, 17 Oct 2008 19:49:00 -0000 From: Michael Snyder User-Agent: Thunderbird 1.5.0.12 (X11/20080411) MIME-Version: 1.0 To: Jakob Engblom CC: 'Pedro Alves' , 'Eli Zaretskii' , "teawater@gmail.com" , "gdb-patches@sourceware.org" , "brobecker@adacore.com" Subject: Re: [RFA] Displaced stepping just enable in non-stop mode References: <20081016183217.GA27176@caradoc.them.org> <48F7AEF2.4050405@vmware.com> <200810171548.12752.pedro@codesourcery.com> <48F8CB7E.3060102@vmware.com> <00df01c93091$1b2d3af0$5187b0d0$@com> In-Reply-To: <00df01c93091$1b2d3af0$5187b0d0$@com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes 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: 2008-10/txt/msg00448.txt.bz2 Jakob Engblom wrote: >>> I see, then this means that all the reverse targets in existance >>> implement inserting breakpoints (target_insert_breakpoint, Z packet), >>> instead of relying on memory breakpoints. >> I believe that's true. Certainly it's true for gdb-freeplay. > > Do I understand to mean that the assumption is that the remote-capable target > system > Implements breakpoints by NOT modifying the code, but rather using some other > mechanism that says that certain instructions in memory are breakpoints, and > triggers them appropriately? > > This is what we do in Simics, and this assumptions makes sense to us. > Breakpoints are implemented in the simulator, without any change to the target > system. That's right. The serial protocol message is Z0/z0, and it instructs the target to set/clear a breakpoint (rather than gdb inserting traps into the text section explicitly).