Displaying credits

The system ROM takes care of displaying the credits on the LED displays itself (see MV-LED board).

It's up to the game to display the counts on the screen when needed. SNK recommends using a 8x8 fix layer font.

The credit count for each player is stored in BCD in $D00034 for player 1, and $D00035 for player 2. These locations are in the backup RAM, to keep the credit counts in case of a power failure during play.

Note: SYSTEM_IO must be called each v-blank to update those locations.