Minor coordinates range from 0 to 255. When it becomes 256, it goes to 0 and the major coordinate increases by 1. When it becomes -1, it goes to 255 and the major coordinate decreases by 1.
Level notes
Although levels 7 and 9 are different parts of the same level, it is not possible to go from level 7 directly to level 9, thereby skipping level 8.
See also
Game Resources - we have resource pages for other games too!