Carry/borrow propagate adder/subtractor
US4739503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1986 |
| Grant date | Apr 19, 1988 |
| Priority date | — |
| Expiry date | Apr 21, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2207/3876
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A digital arithmetic combiner having improved overflow signal propagation delay characteristics is disclosed. Such an arithmetic combiner includes a tristate device having a data input terminal coupled to an overflow input terminal and a data terminal coupled to an overflow output terminal. A tristate control terminal is coupled to the output of logic circuitry. The logic circuitry is responsive to operand input signals and enables the tristate device to generate a signal at its data output terminal when the operand input signals have different logic states. In addition, an overflow generator is responsive to the operand input signals, and generates a signal indicating overflow conditions at the overflow output terminal when the operand input signals have the same logic state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.