Four-Valued Reasoning and Cyclic Circuits
Graeme Gange, Benjamin Horsfall, Lee Naish, Harald Sondergaard
IEEE Transactions on Computer - Aided Design of Integrated Circuits and Systems | IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC | Published : 2014
Allowing cycles in a logic circuit can be advantageous, for example, by reducing the number of gates required to implement a given Boolean function, or a set of functions. However, a cyclic circuit may easily be ill behaved. For instance, it may have some output wire oscillation instead of reaching a steady state. Propositional three-valued logic has long been used in tests for good behavior of cyclic circuits; a symbolic evaluation method known as ternary analysis provides one criterion for good behavior under certain assumptions about wire and gate delay. We revisit ternary analysis and argue for the use of four truth values. The fourth truth value allows for the distinction of undefined a..View full abstract
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Awarded by Australian Research Council through ARC grant
This work was supported in part by the Australian Research Council through ARC grant DP110102579. The authors wish to thank the reviewers for detailed feedback that helped improve the paper.