SHIM: A Language for Hardware/Software Integration

Virtually every system designed today is an amalgam of hardware and software. Unfortunately, software and circuits that communicate across the hardware/software boundary are tedious and error-prone to create. This sug-gests a more automatic way to synthesize them. This paper presents the SHIM language, which combines imperative C-like semantics for software and RTL-like se-mantics for hardware to allow a unified description of hard-ware/software systems. Hardware processes and software functions communicate through shared variables, hardware for which is automatically synthesized by the SHIM com-piler, which generates C and synthesizable VHDL. I demonstrate the effectiveness of the language by re-implementing an I2C bus controller. The SHIM source is half the size of an equivalent manual implementation, slightly faster, and has a smaller memory footprint. Partial and complete hardware implementations in SHIM are also pre-sented, showing that SHIM is succinct and effective.