| 摘要 |
PROBLEM TO BE SOLVED: To reduce the circuit scale of the quotient/remainder discriminating part of retracting divider for high-order radix by determining a quotient by performing bit matching corresponding to the compared results of a three-input adder/subtracter, a three-input comparator and second and first comparators. SOLUTION: A quotient/remainder discriminating part 213 is composed of a shifter 310 as a multiple generating means, an N-digit comparator 311 for B<=R, an (N+1)-digit comparator 312 for 2B<=R, an (N+1)-digit three-input comparator 313 for 3B<=R, two-digit 2:1 selectors (first to third selectors) 314-316 for quotient discrimination, (N+1)-digit 2:1 selectors (fourth and fifth selectors) 317 and 318 for (y) and (z), an (N+1)-digit three-input adder/subtracter 319 for finding a new remainder Re and bit matching parts 320 and 321. In the three-input adder/subtracter 319, the new remainder Re is found by parallel performing the compound addition/subtraction of R-(y+z)} with one time of carry propagation. Next, in the matching parts 320 and 321, a quotient Q is determined by performing bit matching corresponding to the compared result of the three-input comparator 313 or the like. |
