We now briefly review two previous burst-mode asynchronous synthesis systems, and compare them to MINIMALIST.
The UCLOCK [] system is a nearly complete path from plain burst-mode specifications to two-level logic. It incorporates a safe, exact state minimization algorithm, and the first exact hazard-free single-output logic minimization algorithm [20]. Unlike MINIMALIST, however, it offers no automated method for state encoding or multi-output logic minimization. 2 Further, its Lisp implementation and slow algorithms for state minimization and logic minimization severely limit its usefulness. Finally, it does not allow fed-back outputs, missing an opportunity to significantly reduce implementation complexity.
The 3D system, presented in [34][36][35], also synthesizes two-level implementations, but accepts extended burst-mode specifications -- a larger class of specifications than either UCLOCK or MINIMALIST (at present) handle. Unlike UCLOCK, 3D uses fed-back outputs; unlike MINIMALIST, their use is not an option: it is required. In contrast to MINIMALIST, it uses heuristic greedy state minimization and encoding algorithms. It also always performs exact single-output logic minimization (using HFMIN [8]), to produce reasonably high-performance implementations. Even so, none of its methods (save HFMIN) offers any guarantee of optimality; benchmarks show that MINIMALIST's algorithms give better results.
Finally, whereas both UCLOCK and 3D support only a single implementation style and one cost function, MINIMALIST supports multiple implementation styles and cost functions. MINIMALIST thus allows designers to explore various trade-offs and choose the implementation which best suits their application.