NES 2.0 Mapper 263

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NES 2.0 Mapper 263 is used for an MMC3 clone with scrambled mapper address and data bits. Its UNIF board name is UNL-KOF97. It is used for two games by Rex Soft:

  • Boogerman II: The Final Adventure
  • The King of Fighters '97


A12 is used for the MMC3's A0:

Mask: $F000

Mapper 263    Regular MMC3
address       address
----------    ------------
8000          8000
9000          8001
A000          A000
B000          A001
C000          C000
D000          C001
E000          E000
F000          E001

The data written to the MMC3 clone has the following bit order compared to a regular MMC3:

Written bit 76543210
Actual bit  76243051

Which means that to get from the written data to the actual data, the following operation must be performed:

Val =(Val &0xD8) | ((Val &0x20) >>4) | ((Val &4) <<3) | ((Val &2) >>1) | ((Val &1) <<2);