Abstract: A functional unit is provided which allows for fast, parallel data read, write, and manipulation operations. The functional unit includes first and second source registers for receiving first and second data items to be processed by the functional unit, a plurality of memory tables, a combinational logic circuit, and a decoder. Each of the tables is indexed by an index comprising a portion of the first data item received by the first source register. The combinational logic circuit receives lookup results, and processes the lookup results and the second data item in the second source register to produce a result data item. The decoder circuit extracts an operational code from an instruction supplied to the functional unit, decodes the operational code, and controls the combinational logic circuit in accordance with the operational code.

Abstract: Microprocessor shifter circuits utilizing butterfly and inverse butterfly circuits, and control circuits therefor, are provided. The same shifter circuits can also perform complex bit manipulations at high speeds, including butterfly and inverse butterfly operations, parallel extract and deposit operations, group operations, mix operations, permutation operations, as well as instructions executed by existing microprocessors, including shift right, shift left, rotate, extract, deposit and multimedia mix operations. The shifter circuits can be provided in various combinations to provide microprocessor functional units which perform a plurality of bit manipulation operations.