An SoC maintains the full flexibility of a general-purpose microprocessor while providing energy efficiency similar to an ASIC by implementing software-controlled virtual hardware architectures that enable the SoC to function as a virtual ASIC. The SoC comprises a plurality of “Stella” Reconfigurable Multiprocessors (SRMs) supported by a Network-on-a-Chip that provides efficient data transfer during program execution. A hierarchy of programmable switches interconnects the programmable elements of each of the SRMs at different levels to form their virtual architectures. Arithmetic, data flow, and interconnect operations are also rendered programmable. An architecture index” points to a storage location where pre-determined hardware architectures are stored and extracted during program execution. The programmed architectures are able to mimic ASIC properties such as variable computation types, bit-resolutions, data flows, and amount and proportions of compute and data flow operations and sizes. Once established, each architecture remains in place as long as needed.