jg-sameboy (Game Boy, GB Color emulation core for Jolly Good Emulation)

SameBoy is an emulator for the Nintendo Game Boy/Game Boy Color.
Source for the emulator core is unmodified from upstream sources.

SameBoy supports "2 Player Mode" via Auxiliary Files. The Auxiliary
File will be loaded as the second game (the first game specified on
the command line in The Jolly Good Reference Frontend, and displayed
on the bottom). Save data will work for both games, but cheats and
states only work for the main game. The link cable and IR sensor are
always considered connected in 2 Player Mode.

Note: jollygood does not automatically use this core (it uses
jg-gambatte for .gb and .gbc files). To use sameboy, you'll have to
give the "-c sameboy" option to jollygood.

By default, no controls are mapped. The first time you run a game,
press Shift-1 to configure the first controller.
