Datapath optimization using feedback

Abstract

Describes recent experience with Fasolt, a software tool that automatically optimizes a register-level datapath. Fasolt uses a model of layout to drive the choice of optimizing transformations at the levels of scheduling and allocation; hence it is a feedback-driven optimization system. In choosing transformations, Fasolt takes placement and wiring into account in a way that has not been demonstrated in any other high-level synthesis system. Fasolt is also cyclic in that high-level transformations trigger changes at lower levels, which after analysis trigger further high-level changes. This implementation of Fasolt has an expanded set of transformation rules, timing-driven and area-driven transformations, and improved layout modeling capability. The authors present experimental results on three basic test cases and two major variations on the layout software.<>