Proceedings 1999 IEEE International Conference on Computer Design: VLSI in Computers and Processors (Cat. No.99CB37040) (1999)
Oct. 10, 1999 to Oct. 13, 1999
K.K. Lee , University of Texas at Austin
D.F. Wong , University of Texas at Austin
We consider technology mapping of combinational circuits onto complex configurable logic blocks (CLBs) with two levels of LUTs.We show that if the CLB has b bases, a tree network with n nodes can be mapped in O(C?n2b-1) time, where C is a function dependent on b. b is fixed for a given CLB architecture. In particular, this algorithm runs in O(n5) time when mapping a circuit of n nodes onto the Xilinx XC4000.To the best of our knowledge, this is the first optimal polynomial time algorithm for mapping any non-trivial network onto such a complex CLB architecture. By simplifying the computation, we obtained an O(n3) algorithm.The mapping results are comparable to the best NP-hard MILP approach, but our algorithm runs in polynomial time and is much faster in practice. The larger MCNC benchmark circuits were mapped in a few minutes. Our algorithm also maps to CLBs with independent, heterogeneous LUTs as a special case.
K. Lee and D. Wong, "An Exact Tree-Based Structural Technology Mapping Algorithm for Configurable Logic Blocks in FPGAs," Proceedings 1999 IEEE International Conference on Computer Design: VLSI in Computers and Processors (Cat. No.99CB37040)(ICCD), Austin, Texas, 1999, pp. 216.