High performance parallel binary byte adder
US4914617A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1987 |
| Grant date | Apr 3, 1990 |
| Priority date | — |
| Expiry date | Jun 26, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2207/382
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A parallel binary byte adder performs addition and subtraction on the individual bytes of an A-operand and a B-operand as well as on the entire A and B operand. An A-operand is input to a special adder circuit. A B-operand is modified in a set up logic circuit, in accordance with the specific operation to be performed, before being input to the special adder circuit. A set/mask logic generates set, mask and carry signals which are further input to the special adder circuit. The special adder circuit includes an auxiliary functions circuit and a pseudo carry circuit for generating a set of variables which are processed by a sum circuit to produce three partial results. The first partial result relates to bits 0-5 of the particular byte being processed, the second relates to bit 6, and the third relates to bit 7. A concatenation of the three partial results produces a final sum or difference of the particular byte or bytes involved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.