CRC operation unit and CRC operation method

A CRC operation unit comprising:

• generating polynomial holding means for holding data representing a generating polynomial;
• and
• CRC operation means for performing CRC operation based on the data representing a generating polynomial and data to be subjected to CRC operation,
• Wherein, when the number of bits of the data representing a generating polynomial is smaller than the number of bits allowed to be held by the generating polynomial holding means, the generating polynomial holding means left-justifies the data representing a generating polynomial and gives 0 to the remaining lower-order bit(s).

A CRC operation method comprising the steps of:

• selectively outputting data representing a generating polynomial or zero data of which all bits have a value of 0;
• outputting operation data to be subjected to CRC operation;
• and
• performing exclusive OR operation between the data representing a generating polynomial or the zero data and the operation data,
• wherein the step of selectively outputting data representing a generating polynomial selects the data representing a generating polynomial or the zero data depending on a value of the MSB of operation results obtained from a preceding step of performing exclusive OR operation, and
• the step of outputting operation data outputs, as the operation data, data composed of:
• values of bits in lower order than the MSB of the operation results obtained from the step of performing exclusive OR operation as values of higher-order bits of the operation data;
• and a value of the MSB of unprocessed data to be subjected to CRC operation as a value of the LSB of the operation data.