INES Mapper 207

 Here are Disch's original notes:  
 ========================
 =  Mapper 207          =
 ========================
 
 
 Example Game:
 --------------------------
 Fudou Myouou Den
 
 
 Notes:
 ---------------------------
 Regs appear at $7EFx, I'm unsure whether or not PRG-RAM can exist at $6000-7FFF
 
 
 
 Registers:
 ---------------------------
 
   $7EF0:  [MCCC CCCC]
      M = Mirroring 0
      C = CHR Reg 0
 
   $7EF1:  [MCCC CCCC]
      M = Mirroring 1
      C = CHR Reg 1
 
   $7EF2-7EF5:  CHR Regs 2-5
 
 
   $7EFA,7EFB:  PRG Reg 0 (8k @ $8000)
   $7EFC,7EFD:  PRG Reg 1 (8k @ $A000)
   $7EFE,7EFF:  PRG Reg 2 (8k @ $C000)
 
 
 CHR Setup:
 ---------------------------
 
        $0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
      +---------------+---------------+-------+-------+-------+-------+
      |    <$7EF0>    |    <$7EF1>    | $7EF2 | $7EF3 | $7EF4 | $7EF5 |
      +---------------+---------------+-------+-------+-------+-------+
 
 PRG Setup:
 ---------------------------
 
       $8000   $A000   $C000   $E000  
     +-------+-------+-------+-------+
     | $7EFA | $7EFC | $7EFE | { -1} |
     +-------+-------+-------+-------+
 
 Mirroring:
 ---------------------------
 
   [ $7EF0 ][ $7EF0 ]
   [ $7EF1 ][ $7EF1 ]
 
 Mirroring bit of appropriate reg selects NTA or NTB