This interface extends the serial_device with
a write_at() function. It is similar to the write()
function of the mentioned interface, but accepts an on-screen character
position. This interface is implemented by text consoles allowing them
to be connected to text oriented frame buffers, such as VGA in text mode.
SIM_INTERFACE(extended_serial) {
void (*write_at)(conf_object_t *obj,
int value, int x, int y, int fg, int bg);
void (*graphics_mode)(conf_object_t *obj, int in_graphics_mode);
};
#define EXTENDED_SERIAL_INTERFACE "extended_serial"