Trying to get Mapper 222 IRQs right

Discuss emulation of the Nintendo Entertainment System and Famicom.

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NewRisingSun
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Joined: Thu May 19, 2005 11:30 am

Re: Trying to get Mapper 222 IRQs right

Post by NewRisingSun » Wed Apr 15, 2020 2:12 pm

Unless one wants to assign two submappers each applying to a single game for disambiguation, getting both Dragon Ninja (CHR bank number nibblized by software) and Super Bros. 8 (CHR bank number nibblized by latch) emulated means ignoring writes to the upper nibble register, and having the lower nibble register take the full eight bits. This works because Dragon Ninja does not AND the lower nibble register data to be written with $0F.

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