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#1
Red Alarm Question
Posted on: 6/10 22:20
Virtual Freak
Joined 2008/8/13
USA
92 Posts
ContributorLong Time User (9 Years)
So a few years ago, Virtual Boy dumping was added to the Retrode.

http://consolingmyself.co.uk/post/732 ... rtual-boy-adapter-build-3

One game doesn't seem to work, however...

Quote:
they all work fine apart from one, Red Alarm.

...

I am not sure why, but it registers as a 512KByte file when it should be a 1024KByte file. The other 1024KByte game I have works fine, so am not sure why this one isnít behaving.


Does Red Alarm use some sort of bank switching other games don't use, or is there some other reason it may appear as only being half the size it should?
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#2
Re: Red Alarm Question
Posted on: 6/18 22:53
PVB Elite
Joined 2008/12/28
Slovenia
606 Posts
Highscore Top ScoreHighscore Top ScoreCoderContributorTop10 Poster10+ Game RatingsLong Time User (8 Years) App CoderPVBCC 2010 EntryPVBCC 2013 Entry
Since no one else wants to have a shot...

I'm not a hardware expert, but I know that no known VB game uses any kind of bank switching. There's no need for it as ROMs can be up to 16 MB in size before bank switching would be needed (or 32 MB by using the address space meant for additional hardware, though it wouldn't be contiguous), and if any game did use it, it wouldn't work on a FlashBoy.

I'm curious what "registering as a 512K file" means, as there is no way for the hardware or software to know how large the ROM is, so if you tried to dump a 512K ROM as a 1 MB ROM, you would just get two identical copies of it (someone correct me if I'm wrong).
Edited by HorvatM on 2017/6/18 23:03
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#3
Re: Red Alarm Question
Posted on: 6/19 5:44
PVB Elite
Joined 2003/7/26
USA
1408 Posts
PVBCC EntryCoderContributorSpecial AchievementTop10 PosterHOTY09 EntryLong Time User (14 Years) App Coder20+ Game RatingsPVBCC 2013 Entry
I agree with HorvatM; without knowing how the firmware in the Retrode decides how big a file should be, any answer given would be pure speculation. It might have a database of sizes which contains an incorrect entry for RA, or it might be using some kind of heuristic which fails with RA for some reason. Is the source-code of the firmware available?

The only foolproof method would be to simply look for repetition in the entire ROM address space (on power-of-two boundaries) and take the repeated block as your ROM. You might also use the data from the header to construct your filename (although I can see how just calling everything "cart.bin" or whatever would make it easier to use with emulators).
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#4
Re: Red Alarm Question
Posted on: 6/22 2:06
Virtual Freak
Joined 2008/8/13
USA
92 Posts
ContributorLong Time User (9 Years)
Thank you both for your replies. While I haven't done any coding for the Retrode, my understanding is that it uses heuristics if there is no ROM size in the header.

The source code is not publicly available, but is available upon request to the creator.
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