tag:blogger.com,1999:blog-1235714562632087542.post6428045481627649126..comments2023-07-14T17:48:00.016+10:00Comments on Retro Ports: One last subtle bugtcdevhttp://www.blogger.com/profile/02245101571269922064noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-1235714562632087542.post-6410178609058923572014-06-12T15:58:58.736+10:002014-06-12T15:58:58.736+10:00The 'state' of the game is more-or-less co...The 'state' of the game is more-or-less contained in a couple of small tables in a single block of memory, plus a couple of zero-page registers. So some sort of process that could trace these values for each platform and compare side-by-side would be just perfect.<br /><br />I've been using the MAME/MESS debugger for over a decade now so I'm reasonably familiar with the feature set, though it's only recently that I've been experimenting with the more advanced features, such as watchpoint triggers that can evaluate expressions (execute commands). I'm not exactly sure whether it can be coaxed to dump memory segments, but I'll certainly be exploring these possibilities.<br /><br />My next plan of attack was to trace the changes on a single zero-page register, as it may give me enough information. But I won't know until I try...<br /><br />Good to know we're thinking along the same lines!<br />tcdevhttps://www.blogger.com/profile/17906878237742487968noreply@blogger.comtag:blogger.com,1999:blog-1235714562632087542.post-96806948496424422014-06-12T09:36:18.687+10:002014-06-12T09:36:18.687+10:00MAME (and I assume MESS) has some tracing faciliti...MAME (and I assume MESS) has some tracing facilities that may be of use. In the simplest case you could have it dump full instruction traces of the original and your port. A little post-processing to line up common routines should be able to track down a divergence.<br /><br />I think it may be possible to have MAME/MESS log state when the PC reaches specified watchpoints. Attaching state logging to some particular routine could give a much simpler trace for comparison purposes.<br /><br />Might be easier than checking by hand, but sometimes there's nothing for it but elbow grease. Either way, good luck!gp2000https://www.blogger.com/profile/02992652811452483354noreply@blogger.com