Rotating Data Blocks

A processing device comprising a plurality of processing units, wherein at least one of the processing units comprises:

• an execution unit configured to execute a computer program instruction to perform a byte-wise rotation operation of an input data block, the execution unit comprising:
• a logic circuit comprising:
• an input data array to receive an input data block comprising N bytes;
• two first layer multiplexer arrays, each first layer multiplexer array configured to:
• receive a first layer data block comprising a respective subset of bytes of the input data block;
• receive a first layer control signal;
• rotate the first layer data block by an amount indicated by the first layer control signal;
• the two first layer multiplexer arrays being configured to respectively output a first rotated first layer data block and a second rotated first layer data block;
• a second layer multiplexer array configured to receive a second control signal, the second layer multiplexer array comprising N multiplexers, each multiplexer configured to select between a corresponding byte of the first and second rotated first layer data blocks based on the second control signal to output a rotated second layer data block, and
• a control signal generator, configured to generate the first layer control signal and second layer control signal based on the received computer program instruction.

A method implemented in an execution unit, the method comprising:

• receiving an input data block comprising N bytes;
• supplying first layer data blocks comprising a respective subset of bytes of the input data block to a first and second first layer multiplexer array;
• supplying a first layer control signal to the first and second first layer multiplexer array;
• rotating the first layer data blocks by an amount indicated by the control signal to output a first rotated first layer data block and a second rotated first layer data block;
• supplying the first rotated first layer data block and the second rotated first layer data block to a second layer multiplexer array, the second layer multiplexer array comprising N multiplexers,
• supplying a second control signal to the second layer multiplexer array to select between a corresponding byte of the first and second rotated first layer data blocks based on the second control signal.