Internet Tools for
Symmetric Bipartite Tables for Accurate Function Approximation
Michael J. Schulte
James E. Stine
EECS Department
Lehigh University

• M. J. Schulte and James E. Stine, ``Approximating Elementary Functions with Symmetric Bipartite Tables,'' in IEEE Transactions on Computers, no. 8, vol. 48, pp. 842-847, August, 1999. (PDF File)
• M. J. Schulte and James E. Stine, ``Symmetric Bipartite Tables for Accurate Function Approximation,'' Proceedings of the 13th IEEE Symposium on Computer Arithmetic, Pacific Grove, California, pp. 175-183, July, 1997. (Postscript File)
• Slides for presentation given at ARITH-13 (Postscript File)

Journal Paper Abstract:

This paper presents a high-speed method for function approximation that employs symmetric bipartite tables. This method performs two parallel table ookups to obtain a carry-save (borrow-save) function approximation, which is either converted to a two's complement number or is Booth encoded. Compared to previous methods for bipartite table approximations, this method uses less memory by taking advantage of symmetry and leading zeros in one of the two tables. It also has a closed-form solution for the table entries, provides tight bounds on the maximum absolute error, and can be applied to a wide range of functions. A variation of this method provides accurate initial approximations that are useful in multiplicative divide and square root algorithms.

SBTM Tools:

• Tarred and gzipped directory containing the SBTM code and documention
• C++ program which tabulate results in the paper
• Header file for program to tabulate results in the paper
• Sample input files for 12-bit operands for cosine
• Document describing sample input file and its possible values
• The Symmetric Table Addition Method (STAM)