Tuesday, August 11, 2009

Outrun Decompilation Oddities

The decompilation is moving along reasonably nicely. I've slowly picking up a decent understanding of the game code.

One interesting thing with the decompilation is that it uncovers code routines and text that don't appear to be in the final game.

For example, check the strings in the following screenshot:


BIN CHAN E
COLOR BANK GA TARINA NOYO !
1 STAGE 127 KO INAINI SHITENE

If you set the program counter to 0x7644 (by typing pc=0x7644) in the mame debugger, and resume execution you will see for yourself.

Any idea if this string is used, or whether it means anything interesting?

UPDATED: Thanks to bluepillnation who points me towards the following link relating to Space Harrier.

Firstly, the text can be translated roughly as follows:

To BIN CHAN
Color bank is lacking.
Make it less than 127 for one stage. 


Bin Chan is a developer who worked on OutRun, Space Harrier and Afterburner. He is listed as BIN in the hi-score table.

It's suggested that this is some kind of protection. "Sega use the MCU to copy tilebank values on most of the system16 games, maybe they use it to copy a colour bank value on space harrier too, but it's not obvious until you get to that stage".

1 comment:

bluepillnation said...

Argh - didn't mean to post that last one...

It looks like a copy-protection thingummy, and it's been in the setup since Space Harrier apparently:

http://www.mameworld.info/ubbthreads/showflat.php?Cat=&Number=133634&page=12&view=expanded&sb=1&o=&fpart=1&vc=1