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Implementation of Four Common Functions on an LNS Co-Processor
January 1995 (vol. 44 no. 1)
pp. 155-161

Abstract—We propose a scheme for evaluating four commonly used functions namely, 1) inverse trigonometric functions, 2) trigonometric functions, 3) the exponential function, and 4) the logarithmic function with the help of a logarithmic number system (LNS) processor. A novel idea of series folding has been introduced for computing the above functions, expressed in the form of infinite series. We also show that with a suitable choice of the radix for the LNS we can evaluate exponential and logarithmic functions without using any extra hardware.

Index Terms—Logarithmic number system, series folding, inverse trigonometric functions, arctangent function, trigonometric functions, exponential function, logarithmic function.

[1] E. E. Swartzlander and A. G. Alexopoulous,“The signed logarithm number system,”IEEE Trans. Comput., vol. C-24, pp. 1238–1242, Dec. 1975.
[2] F. J. Taylor, R. Gill, J. Joseph, and J. Radke,“A 20 bit logarithmic number system processor,”IEEE Trans. Comput., vol. 37, pp. 190–200, Feb. 1988.
[3] D. M. Lewis,“An architecture for addition and subtraction of long word length numbers in the logarithmic number system,”IEEE Trans. Comput., vol. 39, pp. 1325–1336, Nov. 1990.
[4] H.-Y. Lo and Y. Aoki,"Generation of a precise binary logarithm with difference grouping programmable logic array," IEEE Trans. Computers, vol. 34, no. 8, pp. 681-692, Aug. 1985.
[5] J. F. Hart, E. W. Cheney, C. L. Lawson, H. J. Maehly, C. K. Mesz\lenyi, J. R. Rice, H. G. Thacher, Jr., and C. Witzgall,Computer Approximations. New York: John Wiley, 1968.

Debasish Das, Krishnendu Mukhopadhyaya, Bhabani P. Sinha, "Implementation of Four Common Functions on an LNS Co-Processor," IEEE Transactions on Computers, vol. 44, no. 1, pp. 155-161, Jan. 1995, doi:10.1109/12.367997
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