> > the hardware is different (Aes lacks things like the watchdog timer) MAME treats > them > > as different machines. > > Wow, I didn't know this. I always thought the main difference between MVS and AES > were the video & audio output (since a TV would not use your typical arcade > connectors) and a different bios.
No, there are other subtle differences too, it's how some of the protection schemes work even - the MVS codepaths in a number of the mid-late period games will sit in a loop waiting for the watchdog timer to reset them, if that doesn't happen they'll display a 'for use only on original MVS hardware' screen (or sometimes break the game in subtle ways) once that check has passed the status is saved in sram so it doesn't happen again tho. This was done to prevent AES owners using an MVS bios or otherwise hacking their AES system to run the games in MVS mode.
That's why some of the neogeo arcade games in MAME will do the reset process twice on startup, the additional reset is the one done by the watchdog timer.
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