Logic-in-Memory: A Nano Magnet Logic Implementation

In most computational systems memory access represents a relevant bottleneck for circuits performance. The execution speed of algorithms is severely limited by memory access time. An emerging technology like Nano Magnet Logic (NML), where its magnetic nature leads to an intrinsic memory ability, represents therefore a very promising opportunity to solve this issue. Nano Magnet Logic is the ideal candidate to implement the so called Logic-In-Memory (LIM) architecture. But how is it possible to organize an architecture where logic and memory are mixed and not separated entities? In this paper we try to address this issue presenting our recent developments on LIM architectures. We originally conceived a LIM architecture without considering any technological constraints. Here we present the first adaptation of that architecture to Nano Magnet Logic technology. The architecture is based on an array of identical cells developed on three virtual layers, one for logic, one for memory and one for information routing. These three virtual layers are mapped on two physical layers exploiting all our recent improvements on Nano Magnet Logic technology, which are validated with the help of low level simulations. The structure has been tested implementing two different algorithms, a sort algorithm and an image manipulation algorithm. A complete characterization in terms of area and power is reported. The structure here presented is therefore the first step of an ongoing effort directed toward the development of truly innovative architectures.