Object lifetime control in an object-oriented memory protection mechanism

Patent 5075848 Issued on December 24, 1991. Estimated Expiration Date:

December 22, 2009. 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

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Inventors

Application

No. 455585 filed on 12/22/1989

US Classes:

711/152, Memory access blocking711/156Status storage

Examiners

Primary: Fleming, Michael R.
Assistant: Sheikh, Ayaz R.

Attorney, Agent or Firm

Lamb; Owen L.

Foreign Patent References

63-58558 JP. 03/13/1988
3192145 JP. 08/13/1988

International Classes

G06F 009/34
G06F 012/00
G06F 012/04
G06F 012/06

Abstract

An object-oriented computer architecture in which access descriptors include an object index for selecting an object in the address space, and a rights field specifying the permissible operations on a bi-paged object selected by the access descriptor. A local object lifetime bit is provided in the encoded fields portion of access descriptors, object descriptors, and page table entries to determine the lifetime of an object. The AD lifetime bit in the encoded fields of AD is compared in OTE Lifetime Check Logic with the destination object lifetime, the OTE local bit in the encoded fields of the OTE access descriptor. The OTE local bit in the encoded fields of the OTE is compared in PDTE Lifetime Check Logic with the destination object lifetime, the PDTE local bit in the encoded fields of the PDTE access descriptor. The PDTE local bit in the encoded fields of the PDTE is compared in PTE Lifetime Check Logic with the destination object lifetime, the PTE local bit in the encoded fields of the PTE access descriptor. If any of these checks fails, a protection lifetime fault is asserted.