Lib.rs

compute crcs using the ccitt polynomial efficiently without tables

P(x) = x16 + x12 + x**5 + 1

MSB polynomial: 0x8810 MSB polynomial (with explicit 1): 0x1021

https://users.ece.cmu.edu/~koopman/crc/c16/0x8810.txt

The method used is described in a few places:

• Greg Cook provides some commented 6502 asm
• Jon Buller describes how to determine it through automated symbolic calculation and provides some 8051 asm
• adapted by others into C
• the same method is used in avr-libc's _crc_ccitt_update function.