Programmable control latch mechanism for a data processing system

Patent 4179738 Issued on December 18, 1979. Estimated Expiration Date:

June 23, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3292151

Address extending control unit Patent #: 4037211
Issued on: 07/19/1977
Inventor: Ikuta , et al.

Inventors

Application

No. 05/918223 filed on 06/23/1978

US Classes:

712/205, INSTRUCTION FETCHING101/93.04, Segmented print character printers (e.g., dots, etc.)712/208INSTRUCTION DECODING (E.G., BY MICROINSTRUCTION, START ADDRESS GENERATOR, HARDWIRED)

Examiners

Primary: Zache, Raulfe B.

Attorney, Agent or Firm

Bee; Richard E.

International Classes

G06F 9/318 (20060101)
G06F 9/355 (20060101)
G06F 12/06 (20060101)
G06F 9/34 (20060101)
G06F 9/30 (20060101)

Abstract

A programmable control latch mechanism which is particularly useful in a microprocessor. One or more control latches are provided which can be set or reset under direct program control directly from the instruction register of a data processor by the loading therein of a unique program instruction. The unique instruction includes for each control latch two predetermined bit positions, one of which determines whether or not the control latch is to be changed and the other of which determines the binary value to which the control latch is to be changed. This enables anywhere from one to all of the control latches to be changed by a single instruction and enables each latch which is changed to be changed to any desired binary value. The control latch outputs can be used for storage page selection, direct control of external devices or circuits, selection of internal processor functions and the like.