Apparatus for decimal multiplication
US4677583A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1984 |
| Grant date | Jun 30, 1987 |
| Priority date | — |
| Expiry date | Jun 27, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F7/4915
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for decimal multiplication divides a multiplier of binary coded decimal (BCD) into plural groups, generates plural partial products of which are multiplied a multiplicand of BCD and the plural groups of multiplier over successive cycles and adds them to an intermediate product which is a summation of the previously generated partial products. The addition of the partial product and the intermediate product is made by a carry save adder. At a first cycle, the intermediate product is set to zero, and the addition of 6 is made to each digit of either one of the intermediate product sum and the partial product, and the addition of the partial product and the intermediate product is made by a carry save adder loop over successive cycles. At a final cycle, the sum and carry from the carry save adder are added by a full adder, and the subtraction of 6 is made for each digit according to the existence of carry transfer in each digit of the full adder and the resultant value is output as a multiplication result.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.