A decoder and decoding method are described, in which a syndrome is calculated
from a codeword in a syndrome generator, an error polynomial is generated based
upon the syndrome in an error polynomial generator, an error location is determined
from the error polynomial in the error location generator, an error magnitude is
calculated from the error polynomial in the error magnitude generator and the codeword
is corrected by a error corrected codeword generator responsive to location and
error magnitude. An intra-decoder block messaging scheme is described in which
one or more components generate inactivity messages to signal an ability to process
data corresponding to a next codeword. A dual Chien search block implementation
is described in which Chien block is used to determine the number of errors corresponding
to a specified codeword, separately from error location and magnitude calculations
performed by the Chien/Forney block. An enhanced Chien search cell architecture
is described which utilizes an additional Galois field adder to synchronize the
codeword and error vector, thereby decreasing delay and expense corresponding to
an error correcting block implemented with a LIFO register.
