Support for Game Boy Color 🌈

Description

Now that the classic Game Boy is working quite well it’s time to move to Game Boy Color and implement the required changes to make it work.

Making Pokemon Silver work should be a major priority.

Game Boy Color adds the following main features to the DMG device:

• Color - using color palettes
• Double CPU Speed mode
• Additional 24KB of Working RAM (32KB vs 8KB) - using bank switching
• More PPU RAM to handle color
• Larger and more complex boot ROM

Implementation

Most of the changes are related to new GBC (Game Boy Color) registers and PPU pipeline changes associated with the color support Color palletes.

Additionally, there's a double (CPU) speed mode that allows the CPU to run at 8.388608 MHz instead of the normal 4.194304 MHZ (see specifications).

The boot ROM is different and takes more space more information here.

References