Hi-PASS: a computer-aided synthesis system for maximally parallel digital signal processing ASICs

Hi-PASS, a CAD system for digital signal processor (DSP) architecture synthesis, has been developed to automatically produce maximally parallel VLSI designs for real-time applications. The target DSP applications are the class for which desired sample rates are so high that time sharing of hardware is not feasible. Hi-PASS accepts a C code description of the design to be synthesized and produces a structural description of the final design which can be fabricated using standard cells provided by the Lager IV silicon assembly system. Hi-PASS is a collection of modular tools, several of which contain new techniques within the field of synthesis. C code is converted into a flowgraph using a technique known as symbolic interpretation, including new methods for handling certain types of input-dependent control flow. The HOPS program is a heuristic search flowgraph optimizer tailored for the arithmetic intensive structures necessary for real-time DSP applications. The high throughput rates necessary for these applications also require that retiming be used to provide very short inter-register delay times. A new retiming tool has been developed which allows for computationally efficient bit-level retiming.>