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Asynchronous Parallel Prefix Computation
November 1998 (vol. 47 no. 11)
pp. 1244-1252

Abstract—The prefix problem is to compute all the products $x_1 \otimes x_2 \otimes \cdots \otimes x_k,$ for 1 ≤kn, where $\otimes$ is an associative binary operation. We start with an asynchronous circuit to solve this problem with O(log n) latency and O(n log n) circuit size, with $O(n)\ \otimes\!\!-{\rm operations}$ in the circuit. Our contributions are: 1) a modification to the circuit that improves its average-case latency from O(log n) to O(log log n) time, and 2) a further modification that allows the circuit to run at full-throughput, i.e., with constant response time. The construction can be used to obtain a asynchronous adder with O(log n) worst-case latency and O(log log n) average-case latency.

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Index Terms:
Asynchronous circuits, binary addition, prefix computation, average-case latency.
Rajit Manohar, José A. Tierno, "Asynchronous Parallel Prefix Computation," IEEE Transactions on Computers, vol. 47, no. 11, pp. 1244-1252, Nov. 1998, doi:10.1109/12.736437
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