While doing deprecat.h clean-ups (basically conversion of irq systems in old drivers) I’ve stumbled across one of my oldest nemesis … Chequered Flag by Konami. After some grinding of my teeth and a LOT AND HALF of DASM code studying, I’ve finally nailed it down, it was mostly a rather silly bug with the protection device, checking that a check was true on a port by checking that all the bits were high instead of just one like one could imagine …



Note: I’m not entirely sure that the protection is COMPLETELY emulated, if you know the original game and notice something wrong just let me know via the public channels, thanks in advance.














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