On Tue, Aug 20, 2002 at 10:47:21AM -0700, Scott Dattalo wrote:
> The other night I was looking at:
>
> http://www.geocities.com/SiliconValley/Pines/8659/crc.htm#r19

Yes, I've been reading that doc.  I've been trying to transform
Ashley's code to created a reflected table look as per Section #11 for
the 0x8005 poly.

> You can change the Polynomial, whether it's reversed or not, and table
> width. I never could replicate the tables Ashley had created nor could
> I get the crc code on the above web pages to generate the same CRC's for
> the 0x1021 polynomial. Either the above crc code is wrong, Ashley's code
> is wrong, or I'm wrong. I strongly suspect that I'm missing something.

FWIW, I can use Ashley's C code to produce a 0x8005 CRC-16 table with
correct results.  I'm actually sending the CRC to a device that
rejects the data if the CRC is incorrect, so I've got an "independant
third party" to also verify the results, if you will. :) However, I
have to reflect the data before calling CRC16_Update() and I have to
reflect CRC16_High and CRC16_Low before using them.  I'd like to be
able to build this reflection directly into the table lookup as per
Section 11, but for whatever reason, I'm having some difficulty.

-Dave

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