In-Memory Processing Paradigm for Bitwise Logic Operations in STT–MRAM

In the current big data era, the memory wall issue between the processor and the memory becomes one of the most critical bottlenecks for conventional Von-Newman computer architecture. In-memory processing (IMP) or near-memory processing (NMP) paradigms have been proposed to address this problem by adding a small amount of processing units inside/near the memory. Unfortunately, although intensively studied, prior IMP/NMP platforms are practically unsuccessful because of the fabrication complexity and cost efficiency by integrating the processing units and memory on the same chip. Recently, emerging nonvolatile memories provide new possibility for efficiently implementing the IMP/NMP paradigm. In this paper, we propose a cost-efficient IMP/NMP solution in spin-transfer torque magnetic random access memory (STT-MRAM) without adding any processing units on the memory chip. The key idea behind the proposed IMP/NMP solution is to exploit the peripheral circuitry already existing inside memory (or with minimal changes) to perform bitwise logic operations. Such an IMP/NMP platform enables rather fast logic operations as the logic results can be obtained immediately through just a memory-like readout operation. Memory read and logics not, and/nand, and or/nor operations can be achieved and dynamically configured within the same STT-MRAM chip. Functionality and performance are evaluated with hybrid simulations under the 40 nm technology node.