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US5325496A Expired / Lapsed US ⏱️ 0.0 years remaining

Selectable pointer validation in a computer system

Assignee: Intel Corp
•
Filing: 1991-12-24
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Granted: 1994-06-28
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Expires: 2011-12-24
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Abstract

Abstract A computer system is described having selectable pointer validation. The pointer structure is modified to provide selectable pointer validation. Each pointer comprises an effective address portion and a validation enable field. The effective address portion defines the memory location referenced by the pointer. The validation enable field comprises one or more bits of information that indicate whether or not selectable pointer validation is enabled for the particular pointer. Prior to executing a pointer reference, a processor first loads the desired condition of the validation enable field of the pointer. In normal practice of the invention, a programmer would enable selective pointer validation for particular pointers under debug testing or pointers for which a problem may have been encountered. For those pointers for which selective pointer validation is disabled, the pointer reference to the specified effective address occurs without any pointer validation processing. If, however, selective pointer validation is enabled by setting the appropriate value in the validation enable field, additional processing steps are performed by the present invention in order to validate the access being made by the pointer. The pointer access is validated by comparing the effective address portion of the pointer with pointer access information maintained in a pointer descriptor table. The pointer descriptor table contains a pointer descriptor for each allocated pointer. The pointer descriptor for each allocated pointer comprises pointer access information including a base address, a limit address, and access privilege information or a protection value.

Inventors

  • 👤 Kirk I. Hays
  • 👤 Wayne D. Smith

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 09:03
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/36; G06F11/362; G06F12/00; G06F12/14; G06F12/1416; G06F12/1425; G06F12/1441; G06F12/1458; G06F12/1483

Claims Analysis

Total Claims: 18
Claim 1
Independent Claim 82 words
In a computer system having a processor and a memory, a selective pointer validation system comprising: a pointer having an effective address and a validation enable portion, said pointer for referencing a location in said memory corresponding to said effective address; and processing means for validating a reference made by said pointer, said processing means validating the reference made by said pointer only if said validation enable portion of said pointer is set to a value indicating that pointer validation is enabled.
Claim 2
Dependent Claim 82 words
In a computer system having a processor and a memory, a selective pointer validation system comprising: a pointer having an effective address and a validation enable portion, said pointer for referencing a location in said memory corresponding to said effective address; and processing means for validating a reference made by said pointer, said processing means validating the reference made by said pointer only if said validation enable portion of said pointer is set to a value indicating that pointer validation is enabled.
Claim 3
Dependent Claim 21 words
The pointer validation system as claimed in claim 1 wherein said validation enable portion of said pointer is a single bit.
Claim 4
Dependent Claim 25 words
The pointer validation system as claimed in claim 1 wherein said processing means further includes means for reading said validation enable portion of said pointer.
Claim 5
Dependent Claim 34 words
The pointer validation system as claimed in claim 1 wherein the same location in said memory is referenced by said effective address regardless of the state of said validation enable portion of said pointer.
Claim 6
Dependent Claim 37 words
The pointer validation system as claimed in claim 1 further including means for preventing access to said location in said memory referenced by said effective address if said processing means determines that said pointer reference is invalid.
Claim 7
Dependent Claim 43 words
The pointer validation system as claimed in claim 1 further including a pointer descriptor table for storing a plurality of pointer descriptors, each pointer descriptor of said plurality of pointer descriptors being associated with a pointer, said pointer descriptors defining pointer access information.
Claim 8
Dependent Claim 29 words
The pointer validation system as claimed in claim 6 wherein said pointer access information includes one or more base addresses, one or more limit addresses, and access privilege information.
Claim 9
Dependent Claim 21 words
The pointer validation system as claimed in claim 7 wherein said access privilege information includes read, write, or execute privilege information.
Claim 10
Dependent Claim 81 words
In a computer system having a processor and a memory, a process for selectively validating a pointer comprising the steps of: providing a pointer having an effective address and a validation enable portion, said pointer being used for referencing a location in said memory corresponding to said effective address; and validating a reference made by said pointer, said reference being validated only if said validation enable portion of said pointer is set to a value indicating that pointer validation is enabled.
Claim 11
Dependent Claim 81 words
In a computer system having a processor and a memory, a process for selectively validating a pointer comprising the steps of: providing a pointer having an effective address and a validation enable portion, said pointer being used for referencing a location in said memory corresponding to said effective address; and validating a reference made by said pointer, said reference being validated only if said validation enable portion of said pointer is set to a value indicating that pointer validation is enabled.
Claim 12
Dependent Claim 19 words
The process as claimed in claim 9 wherein said validation enable portion of said pointer is a single bit.
Claim 13
Dependent Claim 21 words
The process as claimed in claim 9 wherein said validating step further includes reading said validation enable portion of said pointer.
Claim 14
Dependent Claim 32 words
The process as claimed in claim 9 wherein the same location in said memory is referenced by said effective address regardless of the state of said validation enable portion of said pointer.
Claim 15
Dependent Claim 37 words
The process as claimed in claim 9 further including a step of preventing access to said location in said memory referenced by said effective address if said pointer reference is invalid as determined in said validating step.
Claim 16
Dependent Claim 45 words
The process as claimed in claim 9 further including a step of storing a plurality of pointer descriptors in a pointer descriptor table, each said pointer descriptor of said plurality of pointer descriptors being associated with a pointer, said pointer descriptors defining pointer access information.
Claim 17
Dependent Claim 23 words
The process as claimed in claim 14 wherein said pointer access information includes a base address, a limit address, and access privilege information.
Claim 18
Dependent Claim 19 words
The process as claimed in claim 15 wherein said access privilege information includes read, write, or execute privilege information.

References Cited (Backward Citations)

US4241396A Cited
US4355355A Cited
US5093785A Cited
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US4853849A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1997-06-27 1997-12-27 1998-06-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2001-06-27 2001-12-27 2002-06-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2005-06-27 2005-12-27 2006-06-28 $7700.00 Window Closed / Lapsed

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