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Logic Synthesis n -Basic Concepts and Tools n Tao Lin n Ohio Universtiy n February 17, 1998
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n Introductory to some basic concepts; n Espresso; n Brief description to the BDD (Binary Decision Diagram).
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F oundation for: n combinational and sequential synthesis n testing n timing and false paths n formal verication n asynchronous synthesis n automata theory n optimal clocking schemes n hazard analysis n power estimation n general combinatorics.
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if f 1 = B n, f is the tautology, i.e. f 1; if f 0 = B n, (f 1 = ) f is not satisfiable; if f(x) = g(x) for all x B n, then f and g are equivalent; x 1 ; x 2 ; … are variables; x 1 ; x 1 ; x 2 ; x 2 ; … are literals;
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A cover is prime irredundant if all its cubes are prime (irredundant). A prime of f is essential (essential prime) if there is a min-term (essential vertex) in that prime but in no other prime.
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Shannon (Boole) Cofactors
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Binary Recursion Tree
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Unate Functions and Unate Covers A function is unate in x i if it is either positive unate or negative unate in x i.
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Unate covers F have many extraordinary properties: If a cover F is minimal with respect to singlecube containment, all of its cubes are essential primes. In this case F is the unique minimum cube repre- sentation of its logic function. A unate cover represents the tautology iff it contains a cube with no literals, i.e. a single tautologous cube.
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IRREDUNDANT
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EXPAND
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Main idea of EXPAND
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REDUCE
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Reduce is order dependent.
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REDUCE Algorithm
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Unate Algorithm for SCCC
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LSTGASP
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A Brief Description of BDD (Binary Decision Diagram)
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Acknowledgement n Most of the materials used here were selected from EE219b course note of UC- Berkeley. The author of these notes is Mr. R.K.Brayton. n Many thanks to people who give me help on preparing this talk.
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