1. A machine-readable medium having stored thereon a set of instructions for execution on a computer, said instructions when executed by the computer perform a method for evaluating a first periodic function utilizing a special number comprising: providing argument reduction of an original argument such that a floating-point representation of .pi./2 having a reduced number of bits is stored within said computer comprising: selecting a special number P.sub.j based upon a bit length of a register of said computer; subtracting from said original argument a first non-negative integer multiple of said special number P.sub.j to obtain a first reduced argument; and subtracting from said first reduced argument a second non-negative integer multiple of said floating-point representation of .pi./2 to obtain a second reduced argument; evaluating a second periodic function at a third argument equal to a sum of said second reduced argument plus a product of said first non-negative integer multiple and a floating-point representation of a second number .delta..sub.j, said second number .delta..sub.j being shifted off a selected number of bit positions from said special number P.sub.j ; and outputting a value of said first periodic function evaluated at said original argument utilizing said second periodic function evaluated at said third argument.