A scalable symbolic simulation tool for low power embedded systems

Recent work has demonstrated the effectiveness of using symbolic simulation to perform hardware software co-analysis on an application-processor pair and developed a variety of hardware and software design techniques and optimizations, ranging from providing system security guarantees to automated generation of application-specific bespoke processors. Despite their potential benefits, current state-of-the-art symbolic simulation tools for hardware-software co-analysis are restricted in their applicability, since prior work relies on a costly process of building a custom simulation tool for each processor design to be simulated. Furthermore, prior work does not describe how to extend the symbolic analysis technique to other processor designs. In an effort to generalize the technique for any processor design, we propose a custom symbolic simulator that uses iverilog to perform symbolic behavioral simulation. With iverilog - an open source synthesis and simulation tool - we implement a design-agnostic symbolic simulation tool for hardware-software co-analysis. To demonstrate the generality of our tool, we apply symbolic analysis to three embedded processors with different ISAs: bm32 (a MIPS-based processor), darkRiscV (a RISC-V-based processor), and openMSP430 (based on MSP430). We use analysis results to generate bespoke processors for each design and observe gate count reductions of 27%, 16%, and 56% on these processors, respectively. Our results demonstrate the versatility of our simulation tool and the uniqueness of each design with respect to symbolic analysis and the bespoke methodology.