A method, performed by a data processor, for processing electromagnetic signals representing convolutionally encoded data streams of bit length L, the method comprising: while performing a trellis search of a convolutionally encoded data stream of bit length L: storing decision bits representing results of the trellis search for the first D bits of the data stream in a (D x N)-bit register accessible by the processor, and ordering the stored decision bits according to the results of the trellis search for the first D bits of the data stream; and storing decision bits representing results of the trellis search for the subsequent L - D bits of the data stream in random access memory accessible by processor; upon completion of the trellis search for the first D bits of the data stream, commencing, starting with the (D + 1) st bit of the data stream, a first trace-forward process to determine a state position at a final winning state position of the trellis search used in outputting the decision bits stored in the register corresponding to the first D bits of the data stream; upon completion of the trellis search for the first P bits of the data stream, where P is greater than D, commencing, starting with the (P + 1) st bit of the data stream, a second trace-forward process to determine a state position at the final Winning state position of the trellis search used in initiating trace-back of the decision bits stored in the random access memory corresponding to the (D + 1) st through P th bits of the data stream; commencing, starting with the state position determined by the second trace-forward process, a first trace-back process for the decision bits stored in the random access memory corresponding to the (D + 1) st through P th bits of the data stream, and storing the resultant decoded bits in a first memory; and commencing, starting with the final winning state position of the trellis search, a second trace-back process for the decision bits stored in the random access memory corresponding to the (P + 1) st through L th bits of the data stream, and storing the resultant decoded bits in a second memory. while performing a trellis search of a convolutionally encoded data stream of bit length L: storing decision bits representing results of the trellis search for the first D bits of the data stream in a (D x N)-bit register accessible by the processor, and ordering the stored decision bits according to the results of the trellis search for the first D bits of the data stream; and storing decision bits representing results of the trellis search for the subsequent L - D bits of the data stream in random access memory accessible by processor; storing decision bits representing results of the trellis search for the first D bits of the data stream in a (D x N)-bit register accessible by the processor, and ordering the stored decision bits according to the results of the trellis search for the first D bits of the data stream; and storing decision bits representing results of the trellis search for the subsequent L - D bits of the data stream in random access memory accessible by processor; upon completion of the trellis search for the first D bits of the data stream, commencing, starting with the (D + 1) st bit of the data stream, a first trace-forward process to determine a state position at a final winning state position of the trellis search used in outputting the decision bits stored in the register corresponding to the first D bits of the data stream; upon completion of the trellis search for the first P bits of the data stream, where P is greater than D, commencing, starting with the (P + 1) st bit of the data stream, a second trace-forward process to determine a state position at the final Winning state position of the trellis search used in initiating trace-back of the decision bits stored in the random access memory corresponding to the (D + 1) st through P th bits of the data stream; commencing, starting with the state position determined by the second trace-forward process, a first trace-back process for the decision bits stored in the random access memory corresponding to the (D + 1) st through P th bits of the data stream, and storing the resultant decoded bits in a first memory; and commencing, starting with the final winning state position of the trellis search, a second trace-back process for the decision bits stored in the random access memory corresponding to the (P + 1) st through L th bits of the data stream, and storing the resultant decoded bits in a second memory.