Fasolt: a program for feedback-driven data-path optimization

The author describes Fasolt, a system that automatically optimizes the bus topology of a register-level data-path design. The unique aspect of Fasolt is that it uses information taken from a detailed layout model to choose optimizing transformations of the bus topology and the schedule of operations and transfers of an existing design. Such a system is called a feedback-drive system because it uses information derived at a low level (in this case, that of physical layout) to drive the selection of optimizing transformations at a higher level or levels (in this case, the scheduling and allocation levels). This allows the scheduling and topology synthesis steps to take wiring considerations into account in a way that has hitherto not been demonstrated in an automatic synthesis system. Experiments have shown that improvements in area, cycle time, and overall average delay can often be achieved in the same design using this approach