Huffman encoding method, circuit and system employing most significant bit change for size detection

摘要

A data processor Huffman encodes a series of multibit signed digital numbers determining the needed data size by detecting the bit position of the greatest significant bit that differs from the most significant bit. Either a left most bit change detector (237) determines this bit position or a left most one detector (237) determines this bit position from the absolute value of the multibit signed digital number. A set of least significant bits equal in number to the data size are selected from the multibit signed digital number. The data processor formed the Huffman encoded signal by concatenating the data size and the selected least significant bits if the original multibit signed digital number was greater than or equal to zero, or by concatenating the data size with the sum of the selected bits and a multibit digital constant having a number of "1's" equal to the data size. A Huffman encoded string of data is formed by concatenating Huffman encoded signals of the next multibit signed digital number with Huffman encoded signals of prior multibit signed digital numbers in the series. This invention is preferably practiced using a data processing circuit (71) having a three input arithmetic logic unit (230), a status register (210), a barrel rotator (235), either a left most bit change detector or a left most one detector (237) and a mask generator (239).