From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20066 invoked by alias); 25 Jan 2016 20:11:15 -0000 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 Received: (qmail 20044 invoked by uid 89); 25 Jan 2016 20:11:15 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:1330, letter X-HELO: ausxippc110.us.dell.com Received: from AUSXIPPC110.us.dell.com (HELO ausxippc110.us.dell.com) (143.166.85.200) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (CAMELLIA256-SHA encrypted) ESMTPS; Mon, 25 Jan 2016 20:11:14 +0000 X-LoopCount0: from 10.170.28.41 From: To: CC: , , Subject: Re: [PATCH] Add a new format letter to dump instructions backward Date: Mon, 25 Jan 2016 20:11:00 -0000 Message-ID: References: <1827952218.466587.1453670934999.JavaMail.yahoo.ref@mail.yahoo.com> <1827952218.466587.1453670934999.JavaMail.yahoo@mail.yahoo.com> <56A609E7.6050903@redhat.com> <2015581.ugHgmqoO9R@ralph.baldwin.cx> <3F40FBEE-2395-4ECC-94A0-A395B35B788C@dell.com> <56A6691A.3060400@redhat.com> In-Reply-To: <56A6691A.3060400@redhat.com> Content-Type: text/plain; charset="Windows-1252" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-IsSubscribed: yes X-SW-Source: 2016-01/txt/msg00633.txt.bz2 > On Jan 25, 2016, at 1:27 PM, Pedro Alves wrote: >=20 > On 01/25/2016 06:22 PM, Paul_Koning@Dell.com wrote: >>=20 >>> On Jan 25, 2016, at 12:52 PM, John Baldwin wrote: >>>=20 >>> On Monday, January 25, 2016 11:41:27 AM Pedro Alves wrote: >>>> On 01/24/2016 09:28 PM, Toshihito Kikuchi wrote: >>>> ... >>>> #3 - negative repeat counts ? >>>>=20 >>>> (gdb) x /4i // next 4 instructions >>>> (gdb) x /-4i // previous 4 instructions >>>> ... >>>> #3 feels natural to me. What do you (and others) think? >>>=20 >>> I think #3 is the most natural as well. I also think this is a >>> very useful feature. >>=20 >> Yes, but how do you do instructions backwards if the instruction length = is variable? It is entirely possible that there will be multiple possible = answers, and no way to tell which one (if any) is "correct". >=20 > You disassemble forward starting from the previous known > instruction boundary, based on symbol/line info. I haven't looked > at the implementation in detail, but from the patch description, that's > what I assume the patch is doing. So unlike the existing x commands this would depend on debug information. = It would be nice if it worked without, on machines where instruction length= is fixed (most RISC machines). paul