INES Mapper 107

Magic Dragon is a side-scrolling shoot-em-up by Magicseries. It is heavily inspired by Irem's R-Type.

Here are Disch's original notes:

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 =  Mapper 107          =
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 Example Game:
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 Magic Dragon
 
 
 Registers:
 ---------------------------
 I do not know whether or not this mapper suffers from bus conflicts.  Use caution!
 
   $8000-FFFF:  [PPPP PPP.]
                [CCCC CCCC]
     P = Selects 32k PRG @ $8000
     C = Selects 8k CHR @ $0000
 
 This is very strange.  Bits 1-7 seem to be used by both CHR and PRG.

FCEUX implements only the bottom 3 bits of the unified register.