[Tutor] i dont understand this code

[Danny Yoo]

It's also a bit unreasonable to ask us to reverse-engineer code that
is orginally CRC-16 code.

Whoever you got this code from is violating the GPL by stripping out
the comments or the COPYRIGHT license from the original sources.  This
is perhaps unintentional.  Please ask them to correct the problem.

The original sources appear to have come from:

    http://dogber1.blogspot.com/2009/05/table-of-reverse-engineered-bios.html