Messages in this thread | | | From | Mike Frysinger <> | Subject | Re: [PATCH 2/8] firmware: Sigma: Skip header during CRC generation | Date | Fri, 25 Nov 2011 15:00:50 -0500 |
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On Friday 25 November 2011 03:55:42 Lars-Peter Clausen wrote: > On 11/24/2011 06:21 PM, Mike Frysinger wrote: > > On Thursday 24 November 2011 07:48:21 Lars-Peter Clausen wrote: > >> The firmware header is not part of the CRC, so skip it. Otherwise the > >> firmware will be rejected due to non-matching CRCs. > > > > that's because you didn't compare to the right value ;). include the CRC > > -> compare to 0. omit the CRC -> compare to the CRC value. > > Does this really work if the CRC is inserted somewhere in the middle of the > bytestream?
i don't think the position matters to the CRC algorithm used by sigmadsp. math principle: a ^ b ^ c is the same thing as b ^ a ^ c and c ^ b ^ a.
i could be wrong as to the CRC algo used though. simple enough for you to check -- i implemented this firmware code based on a spec i wrote up for the sigmadsp peeps; i never actually had real firmware to test with. -mike [unhandled content-type:application/pgp-signature] | |