Processors for network communications

1. A media-access control processor for exchanging data with a physical-layer control unit, the physical-layer control unit interfacing with a communications medium, the media-access control processor comprising:

a first output port to provide data to the physical-layer control unit;

a first input port to receive data from the physical-layer control unit;

a main processor adapted to provide data to the output port and to receive data from the input port;

a CRC coprocessor adapted to generate a cyclic-redundancy-check from an input set of data bytes, the CRC coprocessor having an input to receive an input set of data bytes from the main processor and an output to provide a cyclic-redundancy-check value for the input set of data bytes to the main processor; and

an HCS coprocessor adapted to generate a header-check sequences from an input header, the HCS coprocessor having an input to receive a plurality of bytes of a header from the main processor and an output to provide a header-check sequence therefor to the main processor.

2. The media-access control processor of claim 1 wherein the main processor has a data path having an instruction fetcher, a regular instruction decoder, internal registers, at least one operand bus, an address bus, an output bus, and an extension-instruction decoder; and

wherein at least one coprocessor is responsive to a signal from the extension-instruction decoder and is further adapted to use signals on the at least one operand bus and to place result data on the output bus.

3. The media-access control processor of claim 2 wherein the coprocessor is further adapted to send a stall signal to the main processor.

4. The media-access control processor of claim 2 wherein the at least one coprocessor is further adapted to receive a configuration parameter on the at least one operand bus, the configuration parameter setting a corresponding aspect of the coprocessor's operation.

5. A media-access control processor for exchanging data with a physical-layer control unit, the physical-layer control unit interfacing with a communications medium, the media-access control processor comprising:

a first output port to provide data to the physical-layer control unit;

a first input port to receive data from the physical-layer control unit;

a main processor adapted to provide data to the output port and to receive data from the input port;

a coprocessor adapted to generate one of a cyclic-redundancy-check value or a header-check sequence from an input set of data bytes, the coprocessor having an input to receive an input set of data bytes from the main processor and an output to provide the one of a cyclic-redundancy-check value or the or a header-check sequence to the main processor; and

an cipher coprocessor adapted to generate an output set of data bytes processed according to a ciphering standard, the processing being one of the encryption and decryption process according to the ciphering standard, the cipher coprocessor having an input to receive an input set of data bytes from the main processor and an output to provide a set of processed data bytes to the main processor.

6. The media-access control processor of claim 5 wherein the cipher standard comprises at least one of the Data Encryption Standard and the counter with cipher block chaining messaging authentication code (CCM) protocol Standard.

7. The media-access control processor of claim 5 wherein the main processor has a data path having an instruction fetcher, a regular instruction decoder, internal registers, at least one operand bus, an address bus, an output bus, and an extension-instruction decoder; and

wherein at least one coprocessor is responsive to a signal from the extension-instruction decoder and is further adapted to use signals on the at least one operand bus.

8. The media-access control processor of claim 7 further comprising a set of extension registers accessible to the main processor by the address bus and at least one of the other buses; and

wherein the at least one coprocessor is further adapted to at least obtain data from one or more of the extension registers or store result data to one or more of the extension registers.

9. The media-access control processor of claim 7 the at least one coprocessor is further adapted to place result data on the output bus.

10. The media-access control processor of claim 7 wherein the coprocessor is further adapted to send a stall signal to the main processor.

11. The media-access control processor of claim 7 wherein the at least one coprocessor is further adapted to receive a configuration parameter on the at least one operand bus, the configuration parameter setting a corresponding aspect of the coprocessor's operation.