Dekompozycja wielokrotna z wykorzystaniem SMTBDD

W artykule przedstawiono nową postać binarnych diagramów decyzyjnych zwaną SMTBDD (Shared Multi Terminal Binary Decision Diagrams). Proponowana postać diagramu jest wykorzystywana w procesie dekompozycji funkcji logicznych. Pozwala ona na wygodne wyszukiwanie dekompozycji wielokrotnej, niewymagające wielokrotnej zamiany kolejności zmiennych w diagramach powstających w wyniku cięć diagramu pierwotnego.

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Functional decomposition dedicated to FPGA is the main topic of the article. This paper focuses on the multiple decomposition because it is the most effective method as far as its dynamic property is concerned. The article relates to the problem of carrying out the multiple decomposition using the multi cutting method of BDD diagram. In order to make this problem analysis easier, it is offered to use a new type of a diagram called SMTBBD. In this paper, the properties of SMTBDD diagram are also thoroughly described. Diagrams such as MTBBDD and SBDD were presented as specific forms of SMTBDD diagram. The article represents original calculating techniques of the number of necessary bounded functions. In this case, the notion of a composition layer, which is calculated on the basis of a route table, was introduced. The paper also presents the problem of technology mapping by an appropriate choice of BDD diagram's cutting. At the end of the article, the example of a new technique carrying out the multiple decomposition, is presented.