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US 9,311,246 B2Granted
Cache memory system
AssigneeSTMicroelectronics (Research & Development) Limited
InventorsAndrew Michael Jones, Stuart Ryan
Life of this patent
Estimating the term…
Abstract
Systems and methods are disclosed that comprise a cache memory for storing a copy of a portion of data stored in a system memory and a cache load circuit capable of retrieving the portion of data from the system memory. The systems and methods further comprise a status memory for identifying whether or not a region of the cache memory contains data that has been accessed from the cache memory by an external device.
Claims20
A cache memory system for caching data, comprising:
- a cache memory configured to store a copy of a portion of data stored in a system memory;
- a cache load circuit configured to retrieve the portion of data from the system memory, select a region from a plurality of regions of the cache memory in which to store the retrieved portion of data, and store a copy of the retrieved portion of data in the selected region of the cache memory;
- a tag memory configured to store address information identifying a region of the system memory from which the portion of data stored in the cache memory was retrieved;
- and
- a status memory configured to identify whether a region of the cache memory contains data that has been accessed from the cache memory by a device external to the cache memory system,
- wherein the plurality of regions of the cache memory from which the cache load circuit is configured to select comprises (i) a vacant region, (ii) a region identified as containing data that has been accessed by the device external to the cache memory system, and (iii) a region identified as containing data that has not been accessed by the device external to the cache memory system, and
- wherein the region of the system memory from which the data was retrieved is outside one or more defined address ranges of system memory.
4 more elements
A system, comprising:
- a processor;
- a system memory;
- a cache memory configured to store a copy of a portion of data stored in a system memory;
- a cache load circuit configured to retrieve the portion of data from the system memory, select a region from a plurality of regions of the cache memory in which to store the retrieved portion of data, and store a copy of the retrieved portion of data in the selected region of the cache memory located in between the processor and the system memory;
- a tag memory configured to store address information identifying a region of the system memory from which the portion of data stored in the cache memory was retrieved;
- and
- a status memory configured to identify whether a region of the cache memory contains data that has been accessed from the cache memory by a device external to the cache memory system,
- wherein the plurality of regions of the cache memory from which the cache load circuit is configured to select comprises (i) a vacant region, (ii) a region identified as containing data that has been accessed by the device external to the cache memory system, and (iii) a region identified as containing data that has not been accessed by the device external to the cache memory system, and
- wherein the region of the system memory from which the data was retrieved is outside one or more defined address ranges of system memory.
6 more elements
A method for caching data in a cache memory system, the method comprising:
- retrieving a portion of data from a system memory;
- selecting a region from a plurality of regions of a cache memory in which to store a copy of the retrieved portion of data;
- storing a copy of the retrieved portion of data in the selected region of the cache memory;
- storing address information identifying a region of the system memory from which the portion of data stored in the cache memory was retrieved;
- and
- identifying whether or not a region of the cache memory contains data that has been accessed from the cache memory by a device external to the cache memory system;
- wherein the plurality of regions of the cache memory comprises (i) a vacant region, (ii) a region identified as containing data that has been accessed by the device external to the cache memory system, and (iii) a region identified as containing data that has not been accessed by the device external to the cache memory system, and
- wherein the region of the system memory from which the data was retrieved is outside one or more defined address ranges of system memory.
5 more elements
Dependencies are inferred from the claim text.