Pillsbury Madison & Sutro LLP
Microprocessor having built-in CRC section and method for performing CRC operations using the same
 To provide a microprocessor that can perform high-speed CRC code generation and can be implemented simply and at a low cost, a microprocessor has, at a part of a data input path to a shift circuit which is conventionally installed in an ALU of the microprocessor to execute shift commands, one bit of data that corresponds to the path, an exclusive OR circuit, which computes the exclusive OR of an uppermost bit of byte data and a bit data, is provided. For this circuit, a result according to a generating polynomial such as [X.sup.8 +X.sup.4 +X.sup.3 +X.sup.2 +1] is determined on the basis of the installation location of the exclusive OR circuit along the path, and by setting an initial value to the byte data, inputting one bit of the transmission data sequentially to the bit data and operating the shift circuit, a computed result for the CRC code is derived. Consequently, for the microprocessor, the CRC code can be generated at a high speed using the computation commands of the CRC code section. Corresponding techniques for error-checking of received data are also disclosed. 
Denso Corporation
G H
G06F H03M
additional inventional
Kyouichi Nobutomo Hideaki Akihiro
Suzuki Takagi Ishihara Sasaki