| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for calculating a reciprocal of a square root with which a higher speed operation than that of a square root reciprocal arithmetic circuit using the conventional divider and square root extractor can be carried out and hardwares can be saved. SOLUTION: The method for calculating the reciprocal of a square root when a radix is r supposing that an intermediate result after j times repeated calculation is S[j], a balance is W[j], and the product of an operand X and the intermediate result S[j] is P[j] comprises a step for setting proper values for initial values S[0], W[0], and P[0] and a step for selecting a digit qj+1 of the reciprocal of a square root from a digit set -a,..., -1, 0, 1,..., a} by a digital selecting circuit, and for performing n times repeated arithmetic operation from j=0 to (n-1) concerning a recurrence formula related with the intermediate result S[j]; S[j+1]:=S[j]+qj+1 r<-j-1> , a recurrence formula related with the balance W[j]; W[j+1]:=rW[j]-(2P[j]+Xqj+1 r<-j-1> )qj+1 , and a recurrence formula related with the product P[j]; P[j+1]:=P[j]+Xqj+1 r<-j-1> by using one digit multiplier, adder, and converter.
|
