A Critique on "Asynchronous Logic Implementation Based on Factorized DIMS"

This paper comments on “Asynchronous Logic Implementation Based on Factorized DIMS” [Jour. of Circuits, Systems, and Computers, vol. 26, no. 5, 1750087, pages 9, May 2017] with respect to two problematic issues: i) the gate orphan problem implicit in the factorized DIMS approach discussed in the referenced article which affects the strong-indication, and ii) how the enumeration of product terms to represent the synthesis cost is skewed in the referenced article because the logic expression contains sum of products and also product of sums. It is observed that the referenced article has not provided a general logic synthesis algorithm excepting only an example illustration involving a 3-input AND gate function. The absence of a general logic synthesis algorithm would make it difficult to reproduce the research described in the referenced article. Moreover, the example illustration in the referenced article describes an unsafe logic decomposition which is not suitable for strong-indication asynchronous circuit synthesis. Further, a logic synthesis method which safely decomposes the DIMS solution to synthesize strong-indication asynchronous circuits is already available in the existing literature, which was neither cited nor taken up for comparison in the referenced article, which is another drawback. Subsequently, it is concluded that the referenced article has not advanced existing knowledge in the field but has caused confusions. Hence, in the interest of avid readers, this paper additionally highlights some important and relevant literature which provide valuable information about robust asynchronous circuit synthesis techniques which employ delayinsensitive codes for data representation and processing and the 4-phase return-to-zero handshake protocol for data communication.