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# High Speed Division Algorithm

IP.com Disclosure Number: IPCOM000093488D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 43K

IBM

## Related People

Senzig, DN: AUTHOR

## Abstract

The basic restoring algorithm for division, i.e., the conventional paper and pencil method, and the known nonrestoring algorithms for division are inherently slow. This is because they require approximately either n subtraction or addition cycles or both where n is the word length in bits. These algorithms can be supplemented by one or more speedup techniques. Analysis indicates that such techniques alone cannot improve performance by more than about a factor of four. In any case, the number of iterations is directly proportional to word length, or stated alternatively, convergence is linear or first order.

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High Speed Division Algorithm

The basic restoring algorithm for division, i.e., the conventional paper and pencil method, and the known nonrestoring algorithms for division are inherently slow. This is because they require approximately either n subtraction or addition cycles or both where n is the word length in bits. These algorithms can be supplemented by one or more speedup techniques. Analysis indicates that such techniques alone cannot improve performance by more than about a factor of four. In any case, the number of iterations is directly proportional to word length, or stated alternatively, convergence is linear or first order.

This algorithm is a technique or algorithm for division in which convergence is third order or fourth order. Stated differently, each iteration triples or quadruples the number of correct digits in the quotient. This technique is approximately 50% or 100% faster than previous techniques. This algorithm can be extended to provide still higher order algorithms, but these are probably of lesser interest since, with this fourth order method, a thirty-two bit quotient in two iterations can be generated.

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