void ctl_gfx_controller_move_cursor_at_0x20_0x21(CTL_GFX_CONTROLLER_t *self, int x, int y);
ctl_gfx_controller_move_cursor_at_0x20_0x21 issues the "move cursor" command to an Hitachi-like graphics controller with horizontal and vertical registers at 0x20 and 0x21.