A system for heuristic modifications on PLA-specifications

When specifying a PLA for the implementation of a numerical function, usually an adhoc procedure is followed: Generating real values, some type of scaling, rounding to integers, and finally binary coding. Examining the numerical exactness of the performed steps in detail, some kind of blurring can always be recognized. In fact, designers have to accept such unavoidable effects. In many practical applications a good compromise can be achieved between a reasonable decrease of PLA costs and art acceptable amount of implicated deviation. We introduce in this paper the optimization tool HOPE which includes the described heuristics. It is applicable in any design procedure which needs PLAs and uses ESPRESSO as an integral part.