Abstract: An apparatus, a method and a computer program are provided to reduce leakage current in a processor. Traditionally, extra logic is employed to reduce leakage currents. However, reducing leakage current without sacrificing fine grain operations and speed can be difficult. Achieving such a goal can be accomplished by incorporating a multiplexer (mux) into the scan-in path of scan registers so that units or sub-units of the processor can be powered down individually. Additionally, the muxes are not incorporated into time paths, so speed can be preserved.

Abstract: A disclosed byte execution unit receives byte instruction information and two operands, and performs an operation specified by the byte instruction information upon one or both of the operands, thereby producing a result. The byte instruction specifies either a count ones in bytes operation, an average bytes operation, an absolute differences of bytes operation, or a sum bytes into halfwords operation. In one embodiment, the byte execution unit includes multiple byte units. Each byte unit includes multiple population counters, two compressor units, adder input multiplexer logic, adder logic, and result multiplexer logic. A data processing system is described including a processor coupled to a memory system. The processor includes the byte execution unit. The memory system includes a byte instruction, wherein the byte instruction specifies either the count ones in bytes operation, the average bytes operation, the absolute differences of bytes operation, or the sum bytes into halfwords operation.

Abstract: A method and an apparatus are provided for saving power in a microprocessor. The microprocessor has at least one functional unit, which has a plurality of blocks. The blocks each include a plurality of sub-blocks. It is determined whether there is any instruction for the functional unit. Upon a determination that there is no instruction for the functional unit, the functional unit is shut down. Upon a determination that there is at least one instruction for the functional unit, at least one inactive block of the functional unit is shut down based on the instruction.

Abstract: The present invention provides for saving power in a floating point unit. Bypass logic is coupled to the input of the aligner and the multiplier. An aligner bypass is coupled to the output of the aligner and an output of the bypass logic. A multiplier bypass is coupled to the output of the multiplier and an output of the bypass logic. The aligner bypass and the multiplier bypass transmit the output of the aligner and multiplier, or the bypass logic, as a function of an aligner bypass signal and a multiplier bypass signal, respectively. An adder is coupled to the output of the aligner bypass and the multiplier bypass. Clock disable logic is used to selectively enable and disable at least portions of the aligner, multiplier and bypass logic. This is done based on the operation and on the value of the operands.

Abstract: An apparatus, a method, and a computer program are provided for anticipating leading zeros for a Floating Point (FP) computation. Traditional leading zero anticipators (LZA) are typically very wide. To reduce the width of the LZA, it is subdivided to two smaller LZA that compute edge vectors for the most and least significant bits of intermediate resultant vectors. Therefore, a LZA can be easily folded to reduce the area requirement so as to increase the versatility of the LZA.

Abstract: A method and an apparatus are provided for saving power in a microprocessor. The microprocessor has at least one functional unit, which has a plurality of blocks. The blocks each include a plurality of sub-blocks. It is determined whether there is any instruction for the functional unit. Upon a determination that there is no instruction for the functional unit, the functional unit is shut down. Upon a determination that there is at least one instruction for the functional unit, at least one inactive block of the functional unit is shut down based on the instruction.

Abstract: The present invention provides for saving power in a floating point unit. Bypass logic is coupled to the input of the aligner and the multiplier. An aligner bypass is coupled to the output of the aligner and an output of the bypass logic. A multiplier bypass is coupled to the output of the multiplier and an output of the bypass logic. The aligner bypass and the multiplier bypass transmit the output of the aligner and multiplier, or the bypass logic, as a function of an aligner bypass signal and a multiplier bypass signal, respectively. An adder is coupled to the output of the aligner bypass and the multiplier bypass. Clock disable logic is used to selectively enable and disable at least portions of the aligner, multiplier and bypass logic. This is done based on the operation and on the value of the operands.