---- START NEW MESSAGE --- Received: from cherry.ease.lsoft.com [209.119.0.109] by dpmail10.doteasy.com with ESMTP (SMTPD32-8.05) id A71319FC0218; Thu, 29 Jan 2004 15:28:19 -0800 Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <4.00CC3A4D@cherry.ease.lsoft.com>; Thu, 29 Jan 2004 18:28:08 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8e) with spool id 4673 for PICLIST@MITVMA.MIT.EDU; Thu, 29 Jan 2004 18:28:02 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 7635; Thu, 29 Jan 2004 18:27:45 -0500 Received: from mta07-svc.ntlworld.com [62.253.162.47] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with SMTP ; Thu, 29 Jan 2004 18:27:45 EST X-Comment: mitvma.mit.edu: Mail was sent by mta07-svc.ntlworld.com Received: from BIGVAIO ([80.1.136.189]) by mta07-svc.ntlworld.com (InterMail vM.4.01.03.37 201-229-121-137-20020806) with SMTP id <20040129232235.FKIZ17928.mta07-svc.ntlworld.com@BIGVAIO> for ; Thu, 29 Jan 2004 23:22:35 +0000 References: <2193429B07D9914D97216EBBAA6AB8BD1A0533@whitlam.corp.gli.com.au> <000f01c3e6bb$f7580700$0300a8c0@main> X-Mailer: Forte Agent 1.9/32.560 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Message-ID: Date: Thu, 29 Jan 2004 23:24:53 +0000 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: Mike Harrison Organization: White Wing Logic Subject: Re: [PIC:] Disassemblers To: PICLIST@MITVMA.MIT.EDU In-Reply-To: <000f01c3e6bb$f7580700$0300a8c0@main> Precedence: list X-RCPT-TO: Status: U X-UIDL: 371856368 On Thu, 29 Jan 2004 18:02:26 -0500, you wrote: >Liam O'Hagan wrote: >> It's a Zilog Z86, 1k of code > >If it's just 1K of code, it shouldn't take all that long to start with a >dissassembly listing and end up with commented source code, especially = since >the original source code is still available to answer a lot of = questions. >Just dig in and do it. > several years ago I was involved in reverse-engineering comms protocols = from disassemblies of typically 32-64K of code. I found that by writing my own disassembler, I = could add some simple but useful features to help figure things out - e.g. labelling all the I/O = operations, assigning symbolic names to RAM locations - even simple things like putting a = newline after every jump or return to make breaks in the flow more obvious.=20 A lot of this is very simple if you're writing a disassembler for a = single job - as you discover the functions of various parts, you can add symbols and re-disassemble it to= get a more meaningful listing. It usualy took me about 1-2 days to write a disassembler from scratch (in= interpreted BASIC it doesn't have to be fast or pretty!), although if it's only 1K I'm not = sure it would be worth even that - 1K is really not much code to understand, especially if it wasn't = deliberately written to be obfuscated. =20 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. .