| 摘要 |
PROBLEM TO BE SOLVED: To make an iterative division and/or iterative extraction of square root arithmetic circuit fast by selecting a subset of quotient digit values in advance and shortening a calculation time which passes through the critical of operation. SOLUTION: A dividend A is divided by a divisor D to generate a quotient Q. An iterative dividing circuit 20 calculates a partial residue represented as Pj+1 =rPj -qj+1 D first in each iterative calculation. Here, Pj+j is a partial residue after j+1 iteration, (r) a base, Pj a partial residue after (j) iteration, qj+1 a quotient digit depending upon Pj and D, and a Pj a dividend A when j=0. Then a primary quotient digit selecting circuit selects and stores a subset of quotient digits qj+1 which depend upon D and do not depend upon Pj . Then a secondary quotient digit selecting circuit operates to select a quotient digit qj+1 to be used by the iterative dividing circuit 20 from the stored subset of quotient digits qj+1 which depends upon Pj and do not depend upon D. |
