uint16 get_vram_address();

uint8 vram_mmio_read(uint16 addr);
void vram_mmio_write(uint16 addr, uint8 data);

uint8 oam_mmio_read(uint16 addr);
void oam_mmio_write(uint16 addr, uint8 data);

uint8 cgram_mmio_read(uint16 addr);
void cgram_mmio_write(uint16 addr, uint8 data);