HERCULES-a system for high-level synthesis

This paper presents an approach to high-level synthesis of VLSI processors and systems. Synthesis consists of two phases: behavioral synthesis, which involves implementation-independent representations, and structural synthesis, that relates to the transformation of a behavior into an implementation. We describe HERCULES, a system for high-level synthesis developed at Stanford University. In particular, we address the hardware description problem, behavioral synthesis and optimization using a method called the reference stack, and the mapping of behavior onto a structure. We present a model for control based on sequencing graphs that supports multiple threads of execution flow, allowing varying degree of parallelism in the resulting hardware. Results are then presented for three examples: MC6502, Intel8251 and FRISC, a 16-bit microprocessor.