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Re: [ecc] Decoding different (N,K) combinations
How about just going through the whole thing. Are you sure that the chien
algorithm is the bottle neck of your system, maybe you can just waste a few
clocks and nothing will happen...
Lior
Nimrod Mesika
<nimrodm@beze To: [email protected]
qint.net> cc:
Sent by: Subject: [ecc] Decoding different (N,K) combinations
owner-ecc@ope
ncores.org
06/16/2001
11:14 AM
Please
respond to
ecc
I'm having trouble implementing the Chien search algorithm for
shortened codewords (i.e., N<255 for GF(256)).
It seems like I can do one of the following:
o Start the search from the last byte of the codeword (the lowest
power of alpha, alpha^(-1)) and proceed up to alpha^(-N). Thus,
the output will be in reverse order with respect to the input of
the decoder.
o Start the search from alpha^(-N) and proceed to alpha^(-1). This
is simple if N is constant. However, if N may be different for
different codewords, another set of (non-constant) multipliers are
necessary so that coefficients of lambda(x) and omega(x) will be
multiplied by alpha^(-N) before the search starts.
Of course, this method also requires a ROM table of alpha^(-N)
for every possible N.
I was wondering if there is a simpler method? Anyone?
I'll be happy to provide my C code and (almost finished) verilog
code.
--
Nimrod.
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