The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 13, 1990

Filed:

May. 19, 1987
Applicant:
Inventors:

Thomas F Joyce, Westford, MA (US);

Richard P Kelly, Nashua, NH (US);

Jian-Kuo Shen, Belmont, MA (US);

Assignee:

Bull NH Information Systems Inc., Billerica, MA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ; G06F / ;
U.S. Cl.
CPC ...
364200 ; 364285 ; 3642851 ; 3642852 ; 3642853 ;
Abstract

In a data processing system using a virtual memory addressing scheme, certain software instructions call for the virtual address to be stored in a base register. The virtual address stored in the base register is incremented or decremented during the read out cycle of the previous operand to address the next operand. If the operand is not in physical memory, then the contents of the base register is restored to its original value. This invention minimizes the amount of logic required to back out of a software instruction after execution has begun and is faster than checking if all resources are present before any state change is made during the execution of a software instruction.


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