Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. This work examines the interaction between the physical design of digital integrated circuits and sequential optimization techniques used for performance enhancement. In particular, the integration of floorplanning and placement with retiming and clock skew scheduling is explored. A theoretical result is given which addresses the computational complexity of circuit partitioning under constraints derived from sequential optimization; this motivates the need for heuristic approaches to the related placement problem. Another theoretical result provides a characterization of the feasible retimings of a sequential circuit; this result is used to motivate an effective method for floorplanning integrated with sequential optimization. Practical techniques for using sequential slack to drive standard-cell placement are shown here; experiments demonstrate significant improvement in final design performance using these methods. Another part of this work examines how the role of sequential optimization and physical design changes when the design allows for asynchronous or latency-insensitive communication between modules. A theoretical result relating to the problem of clock tree implementation for clock skew scheduling under process variation is given. Finally an experimental technique for floorplanning using nonlinear programming is demonstrated. All rights reserved.Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission.
Integration of Physical Design and Sequential