INES Mapper 112

This mapper is quite similar to Mapper206; however, the registers are scrambled a bit. You should probably study the documentation below for details instead of referencing Mapper206.

 Here are Disch's original notes:  
 ========================
 =  Mapper 112          =
 ========================
 
 Example Games:
 --------------------------
 Huang Di
 San Guo Zhi - Qun Xiong Zheng Ba
 
 
 Registers:
 ---------------------------
 
 Range,Mask:   $8000-FFFF, $E001
 
 
   $8000:  [.... .AAA]
     A = Address for use with $A000
 
 
   $A000:  [DDDD DDDD]
     Data port:
       R:0 ->  PRG reg 0
       R:1 ->  PRG reg 1
       R:2 ->  CHR reg 0
       R:3 ->  CHR reg 1
       R:4 ->  CHR reg 2
       R:5 ->  CHR reg 3
       R:6 ->  CHR reg 4
       R:7 ->  CHR reg 5
 
 
   $E000:  [.... ...M]
     Mirroring:  0=Vert
                 1=Horz
 
 
 CHR Setup:
 ---------------------------
 
       $0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
     +---------------+---------------+-------+-------+-------+-------+
     |     <R:2>     |     <R:3>     |  R:4  |  R:5  |  R:6  |  R:7  |
     +---------------+---------------+-------+-------+-------+-------+
 
 
 PRG Setup:
 ---------------------------
 
       $8000   $A000   $C000   $E000  
     +-------+-------+-------+-------+
     |  R:0  |  R:1  | { -2} | { -1} |
     +-------+-------+-------+-------+