Magic cells and circuits: New convergence of memory and logic functions in superconductor devices

The finite speed of light sets a fundamental limitation for the time required to communicate between any remote memory and logic devices. This limitation alone implies that the latency of communication cycles between, say, 1-cm processor and memory chips is longer than 120 ps. To bypass this limitation, we propose a novel way of using SFQ cells and devices that eliminates the communication delays by storing and processing information in the same location. We introduce new objects (cells and devices) that store one of input operands, process it during a logic operation that might involve other operands, and replace the initially stored operand by the result of the logic operation. Because these objects execute both Memory And loGIC functions we nicknamed them MAGIC cells and devices. Physically each MAGIC object is either a single flip-flop or composed of flip-flops. MAGIC objects are compatible with, or even may constitute a part of, RSFQ technology. We discuss functional devices built of MAGIC cells. These devices are potentially faster, smaller in size, and have modest requirements for external memory. This is because the suggested functional circuits partly self-satisfy storage needs by utilizing their inherent ability for storing data.