| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiplier having a complete tree of 4-2 compressors structured by signed multiplication. SOLUTION: In a signed multiplier having partial products structured by secondary booth decoding, a booth selector part 101 is provided with a partial- product correcting circuit 103 for correcting the partial products by using a booth decoding output as an input. This reduces the number of partial products and makes it possible to conduct partial product addition of a two-piece tree structure by the 4-2 compressors 104. Carry propagation addition 105 is made to the result of the partial product addition to provide the result of multiplication. Since a complete two-piece tree of 4-2 compressors can be structured especially with 8 bits, 16 bits, and 32 bits, speeding up can be made by a difference in delay time between a two-stage series 3-2 adder and the 4-2 compressors as compared with a conventional structure using a 3-2 adder. |
