Hybrid Spin-CMOS polymorphic logic gate with application in in-memory computing

In this article, we initially present a hybrid spin-CMOS polymorphic logic gate (HPLG) using a novel 5-terminal magnetic domain wall motion device. The proposed HPLG is able to perform a full set of 1- and 2-input Boolean logic functions (i.e., NOT, AND/NAND, OR/NOR, and XOR/XNOR) by configuring the applied keys. We further show that our proposed HPLG could become a promising hardware security primitive to address IC counterfeiting or reverse engineering by logic locking and polymorphic transformation. The experimental results on a set of ISCAS-89, ITC-99, and École Polytechnique Fédérale de Lausanne (EPFL) benchmarks show that HPLG obtains up to 51.4% and 10% average performance improvements on the power-delay product (PDP) compared with recent non-volatile logic and CMOS-based designs, respectively. We then leverage this gate to realize a novel processing-in-memory architecture (HPLG-PIM) for highly flexible, efficient, and secure logic computation. Instead of integrating complex logic units in cost-sensitive memory, this architecture exploits a hardware-friendly approach to implement the complex logic functions between multiple operands combining a reconfigurable sense amplifier and an HPLG unit to reduce the latency and the power-hungry data movement further. The device-to-architecture co-simulation results for widely used graph processing tasks running on three social network data sets indicate roughly 3.6 × higher energy efficiency and 5.3 × speedup over recent resistive RAM (ReRAM) accelerators. In addition, an HPLG-PIM achieves ~4 × higher energy efficiency and 5.1× speedup over recent processing-in-DRAM acceleration methods.