
========================
=  Mapper 189          =
========================


Example Game:
--------------------------
Thunder Warrior


Notes:
---------------------------
This mapper is a modified MMC3.  Everything operates just as it does on the MMC3, only the normal PRG regs
(R:6,R:7) are ignored, and a new PRG Reg is used instead.

For details on MMC3, see mapper 004


Registers:
---------------------------
Regs at $6000-7FFF means no SRAM


  $4120-7FFF:  [AAAA BBBB]
     A,B:  PRG Reg


  $8000-FFFF:  Same as on MMC3


PRG Setup:
--------------------------

'A' and 'B' bits of the $4120 reg seem to be effectively OR'd.
That is... $30, $03, and $21  will all select page 3

     $8000   $A000   $C000   $E000  
    +-------------------------------+
    |             $4120             |
    +-------------------------------+
