INES Mapper 034

iNES Mapper 034 is used to designate both the BNROM and NINA-001 boards.

Emulator authors are suggested to distinguish between these two by checking the number of CHR banks present - BNROM should be used when there is 0 to 8 KiB of CHR, and NINA-001 should be used otherwise. The NES 2.0 header with a submapper can be used to force use of NINA-001 behavior even with 8 KiB of CHR ROM or CHR RAM.

 Here are Disch's original notes:  
 ========================
 =  Mapper 034          =
 ========================
 
 aka
 --------------------------
 BxROM
 NINA-001
 
 
 Example Games:
 --------------------------
 Darkseed               (BxROM)
 Mashou                 (BxROM)
 Impossible Mission 2   (NINA-001)
 
 
 Notes:
 --------------------------
 How these two seperate and completely imcompatible mappers got assigned the same mapper number is a mystery.
 BxROM and NINA-001 are both assigned mapper 034, however they both work totally differently.  There is no
 reliable way to tell the difference between the two apart from a CRC or Hash check.
 
 
 =================================
 BxROM
 =================================
 
 BxROM has bus conflicts... however this mapper also covers some BxROM compatible boards that do
 not suffer from bus conflicts.
 
 
 Registers (**BUS CONFLICTS** sometimes):
 --------------------------
   $8000-FFFF:  Select 32k PRG @ $8000
 
 Note on a real BxROM, only the low 2 bits are used (PRG capped at 128k).  But since this is BxROM and
 compatible, emus should use all 8 bits
 
 
 
 PRG Setup:
 --------------------------
 
        $8000   $A000   $C000   $E000  
      +-------------------------------+
      |             $8000             |
      +-------------------------------+
 
 
 
 =================================
 NINA-001
 =================================
 
 Registers:
 --------------------------
   $7FFD:   Select 32k PRG @ $8000
   $7FFE:   Select 4k CHR @ $0000
   $7FFF:   Select 4k CHR @ $1000
 
 I'm not sure whether or not WRAM can also exist at $6000-7FFF
 
 
 PRG Setup:
 --------------------------
 
       $8000   $A000   $C000   $E000  
     +-------------------------------+
     |             $7FFD             |
     +-------------------------------+
 
 CHR Setup:
 --------------------------
 
       $0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
     +-------------------------------+-------------------------------+
     |             $7FFE             |             $7FFF             |
     +-------------------------------+-------------------------------+