Newton-Raphson’s iterative algorithm is a very popular method to approximate a given function. It can be used to compute reciprocal of a given number. The Newton-Raphson’s iterative equation is

where is the first derivative of . The function which is used to compute the reciprocal of a number is , where D is the input operand. The Newton-Raphson iteration gives

After some finite iterations the above equation converges to the reciprocal of D. It is very obvious that initial value of X ( ) must be chosen care fully to converge. The value of D is scaled to be in the range to chose the initial guess such that few number of iterations required for computation. In this case, D is shifted right or left to be in that range. In that interval of D, one must chose initial value as

The architecture for Newton-Raphson based reciprocal computation is shown below. A serial architecture is given here as parallel architecture is costly and most system architectures uses serial architecture. The pulsed control signal * start* starts the iteration and is the final result. If D is not in the range, pre-processing is required and at the output a post-processing step is also required.

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