A novel and useful apparatus for and method of software based phase locked loop (PLL). The software based PLL incorporates a reconfigurable calculation unit (RCU) that is optimized and programmed to sequentially perform all the atomic operations of a PLL or any other desired task in a time sharing manner. An application specific instruction-set processor (ASIP) incorporating the RCU includes an instruction set whose instructions are optimized to perform the atomic operations of a PLL. The RCU is clocked at a fast enough processor clock rate to insure that all PLL atomic operations are performed within a single PLL reference clock cycle.

An integrated circuit includes a plurality of current-mode computation (CMC) branches, each including a plurality of CMC cells and a branch summation line. An individual CMC cell includes at least one computation transistor that produces a CMC output current that is a function of a channel current of the computation transistor. A branch summation line receives CMC cell output currents produced by a plurality of CMC cells, and produces a branch output current that is a current-mode summation of all received CMC cell output currents. A layer-one current summation circuit receives the branch output current produced by at least one branch summation line, and produces a layer-one current summation circuit output current that is a function of the received branch output currents. The layer-one current summation circuit may be field-programmable. In operation, the integrated circuit can perform transistor tensor operations by programming one or more layer-one current summation circuits to combine all branch output currents received by those layer-one current summation circuits. Using embodiments of the present invention, millions, billions, trillions or more of the CMC cells can be field-programmed to execute computations in parallel to support transistor tensor operations.