internal关键词用于限定成员变量访问范围(没记错的话,C++太久没看了)* H1 n( M" d" u \
FME-7是一块声音芯片,说明如下:& `: H6 N) h& u2 j' B( w) ~
The FME-7 was made by Sunsoft and used as an extension soundchip in Nintendo Famicom / NES Games. It was only used in a single Sunsoft Game (Gimmick!) and is otherwise known as the Mapper 69