06253301 is referenced by 3 patents and cites 9 patents.

A data caching system and method includes a data store for caching data from a main memory, a primary tag array for holding tags associated with data cached in the data store, and a duplicate tag array which holds copies of the tags held in the primary tag array. The duplicate tag array is accessible by functions, such as external memory cache probes, such that the primary tag remains available to the processor core. An address translator maps virtual page addresses to physical page address. In order to allow a data caching system which is larger than a page size, a portion of the virtual page address is used to index the tag arrays and data store. However, because of the virtual to physical mapping, the data may reside in any of a number of physical locations. During an internally-generated memory access, the virtual address is used to look up the cache. If there is a miss, other combinations of values are substituted for the virtual bits of the tag array index. For external probes which provide physical addresses to the duplicate tag array, combinations of values are appended to the index portion of the physical address. Tag array lookups can be performed either sequentially, or in parallel.

Title
Method and apparatus for a dedicated physically indexed copy of the data cache tag arrays
Application Number
9/61626
Publication Number
6253301 (B1)
Application Date
April 16, 1998
Publication Date
June 26, 2001
Inventor
Derrick R Meyer
Austin
TX, US
James B Keller
Waltham
MA, US
David A Webb Jr
Groton
MA, US
Rahul Razdan
Princeton
MA, US
Agent
Hamilton Brook Smith & Reynolds P C
US
Assignee
Compaq Computer Corporation
TX, US
IPC
G06F 12/15
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