Programmable system for invalidating pending requests within a data processing system
First Claim
1. For use in a data processing system having multiple requesting units making requests to multiple receiving units wherein each of the requests includes multiple request data fields, the data processing system further including error indicators each to indicate a respective error condition occurring within the data processing system and wherein each of the error indicators is associated with an error indication value, and is further associated with a respective one of the multiple request data fields, a request invalidation system, comprising:
- a storage unit to store the requests;
a programmable mode control logic to programmably select one of the multiple request data fields as an invalidation field; and
a storage unit control logic coupled to said storage unit, coupled to said programmable mode control logic, and further coupled to detect the assertion of any of the error indicators, said storage unit control logic to cause the removal of any request from said storage unit that has a value stored in said selected invalidation field having a predetermined relationship to the error indication value associated with any of the asserted error indicators that are associated with said invalidation field.
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Accused Products
Abstract
A request invalidation system for invalidating pending requests within a data processing system is disclosed. According to the system of the preferred embodiment, one or more requesting units may make requests to gain access to one or more shared resources. These requests are stored in a central request storage unit and are processed according to a predetermined priority scheme. Each request includes multiple fields for storing information about the request. Within the data processing system, error indicators are provided to indicate the occurrence of a fault, and to further provide an error indication value that provides information about the nature of the fault. Ones of these error indicators are associated with a respective one of the request fields. According to the current request invalidation system, mode control logic is provided to programmably select one of the request fields as the invalidation field. If any error indicator is asserted that is associated with the selected invalidation field, the error indication value for this error indicator is compared against the invalidation field of all pending requests. In the event a predetermined relationship exists between the two compared values, the associated pending request is discarded without being presented to the requested shared resource. According to one aspect of the invention, the invalidation field is selectable by a scan-set interface that may be dynamically re-programmed during normal system operations. According to another aspect of the invention, ones of the error indicators are each associated with a respective requesting unit or a shared resource. Once an error indicator that is associated with a requesting unit or a shared resource has been asserted, no further requests for that requesting unit or shared resource will be stored within the request storage unit until a reset operation is performed. In one embodiment of the current invalidation system, the system includes logic to generate invalidation requests, which are requests to invalidate one or more pending requests based on an invalidation field and error indication value included in the request. The invalidation system further includes logic for using the invalidation field provided by an invalidation request to override the invalidation field that is programmably selected by the scan-set interface.
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Citations
20 Claims
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1. For use in a data processing system having multiple requesting units making requests to multiple receiving units wherein each of the requests includes multiple request data fields, the data processing system further including error indicators each to indicate a respective error condition occurring within the data processing system and wherein each of the error indicators is associated with an error indication value, and is further associated with a respective one of the multiple request data fields, a request invalidation system, comprising:
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a storage unit to store the requests;
a programmable mode control logic to programmably select one of the multiple request data fields as an invalidation field; and
a storage unit control logic coupled to said storage unit, coupled to said programmable mode control logic, and further coupled to detect the assertion of any of the error indicators, said storage unit control logic to cause the removal of any request from said storage unit that has a value stored in said selected invalidation field having a predetermined relationship to the error indication value associated with any of the asserted error indicators that are associated with said invalidation field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
invalidation request generation logic for generating invalidation requests, wherein each of said invalidation requests is one of the error indicators, and wherein each of said invalidation requests selectably indicates one of the multiple request data fields as an invalidation-request selected field; and
wherein said programmable mode control logic includes selection circuits coupled to receive said invalidation-request selected field from said invalidation request generation logic, and to select said invalidation-request selected field as said invalidation field instead of said invalidation field stored by said mode selection storage device.
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8. The request invalidation system of claim 7, wherein said invalidation request generation logic includes timer circuits for generating invalidation requests for those requests that have been pending for greater than a predetermined period of time.
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9. The request invalidation system of claim 6, wherein said programmable mode control logic is further coupled to receive the error indicators, and wherein said programmable mode control logic further includes circuits to automatically override said invalidation field stored by said mode selection storage device based on the reception of error indicators not associated with said invalidation field stored by said mode selection storage device.
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10. A storage device having multiple addressable locations each for storing data entries, wherein each of the data entries includes multiple fields, the memory further for receiving input compare signals to be compared against a selectable one of the multiple fields, the storage device comprising:
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multiple Content Addressable Memories, each having multiple addressable locations to store a respective one of the multiple fields for each of the data entries, wherein each of said CAMs is capable of generating a respective group of CAM compare signals to indicate whether the input compare signals has a predetermined relationship to the signals stored in any of the multiple address locations;
a CAM compare selection circuit coupled to each of said multiple CAMs to receive each of said groups of CAM compare signals; and
a programmable mode selection circuit coupled to said CAM compare selection circuit to cause said CAM compare selection circuit to select one of said groups of CAM compare signals from a selected one of said multiple CAMs that stores a selected one of the multiple fields based on programmable mode selection signals provided by said programmable mode selection circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. For use in a data processing system having multiple requesting units requesting access to multiple receiving units, a request invalidation system, comprising:
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storage means for storing requests provided by a respective one of the multiple requesting units for gaining access to one of the multiple receiving units, wherein each of said requests includes multiple data fields;
error storage means for receiving error indicators each indicative of a fault occurring within the data processing system and each being associated with a respective one of said data fields;
mode selection means for programmably selecting one of said data fields for use as an invalidation field; and
storage address means for removing from said storage means any of said stored requests for which said invalidation field has a predetermined relationship to any of said error indicators that is associated with said one of said data fields selected as said invalidation field. - View Dependent Claims (19, 20)
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Specification