Noel Chiappa writes:
I can't answer that directly, but I will point
you at IEN-56, "CRC
Checksum Calculation", by Dave Reed (11-Sep-78):
https://www.rfc-editor.org/ien/ien56.pdf
I can't help but notice the first program is PDP-10 code for running
on ITS. ObTUHS: the other is a PDP-11 asssembly language program for
Unix. Machine readable versions for both can be procured.