Circuit Retiming: An Incremental Approach

Years and Authors of Summarized Original Work

• 2005; Zhou

Problem Definition

Circuit retiming is one of the most effective structural optimization techniques for sequential circuits. It moves the registers within a circuit without changing its function. The minimal period retiming problem needs to minimize the longest delay between any two consecutive registers, which decides the clock period.

The problem can be formally described as follows. Given a directed graph G = (V, E) representing a circuit – each node v ∈ V represents a gate and each edge e ∈ E represents a signal passing from one gate to another – with gate delays $d : V \rightarrow \mathbb{R}^{+}$ and register numbers $w : E \rightarrow \mathbb{N}$, it asks for a relocation of registers $w^{{\prime}} : E \rightarrow \mathbb{N}$ such that the maximal delay between two consecutive registers is minimized.

Notations To guarantee that the new registers are actually a relocation of the old ones, a label \(r : V \rightarrow...