This game writes to port 3E, if there is no emulation of port 3E there are no problems as the game can't take itself out of the memory map. If you are emulating port 3E however then you will need to take into account that the first value in RAM (0xC000/0xE000) changes what this game writes to port 3E. This is an issue when you are emulating port 3E and have no BIOS loaded for whatever reason.

If you want to emulate port 3E with no BIOS and get this game to run, write 0xAB to 0xC000 before running any z80 code, this is to simulate what the BIOS does in regards to writing the last value written to port 3E in 0xC000.

There is no known reason why this game writes to port 3E as it was only released in cartridge format. However a lot of the mainstream Sega games such as Altered Beast, Alien Syndrome, Alien Storm, etc also do the same thing. It might just be default Sega initialization code.




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