A programmable data communications device is provided to process multiple streams of data according to multiple protocols. The device is equipped with a co-processor including multiple, programmable processors allowing data to be operated on by multiple protocols. The programmable processors within the co-processor include extended instruction sets including instructions providing the operations of zero stuffing, CRC computation, partial compare, conditional move, and trie traversal. These instructions allow the processor(s) of the co-processor to more efficiently execute programs implementing data communications protocols. Since each processor is programmable, protocols standards which change may be accommodated. A network device equipped with the co-processor can handle multiple simultaneous streams of data and can implement multiple protocols on each data stream. The protocols can execute within the co-processor either independently of each other, or in conjunction with each other.