Retiming: Theory and practice

doi:10.1016/S0167-9260(97)00002-3

Integration

Volume 22, Issues 1–2, August 1997, Pages 1-21

https://doi.org/10.1016/S0167-9260(97)00002-3 Get rights and content

Abstract

Retiming is a technique for optimizing sequential circuits. It repositions the registers in a circuit leaving the combinational portion of circuitry untouched. The central objective of retiming is to find a circuit with the minimum number of registers for a specified clock period. There are two common variants of this theme; minimizing the clock period without regard to the number of registers in the final circuit or minimizing the number of registers in the final circuit with no constraints on the clock period.

Over a decade has elapsed since Leiserson and Saxe first presented a theoretical formulation to solve this problem for single-clock edge-triggered sequential circuits. The proposed algorithms have polynomial complexity. Since then research efforts have focussed on incorporating retiming in a synthesis framework, addressing issues that arise due to retiming, and extending the domain of circuits for which retiming can be applied. This paper presents a survey of retiming as it evolved from a theoretical formulation to a powerful optimization technique available in commercial tools. The issues that arise for a practical implementation of the basic retiming formulation are discussed. Some of the relevant research issues and key contributions are presented.

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Retiming: Theory and practice

Abstract

Timing optimization of multi-phase sequential logic

IEEE Trans. Comput. Aided Des.

Optimum retiming of large sequential circuits

Sequential circuit delay optimization using global path delays

Retiming and clock skew for synchronous systems

Automatic determination of optimal clocking parameters in MOS VLSI circuits

Synchronous logic synthesis: Algorithms for cycle-time minimization