Abstract: A memory access control apparatus includes an MIB for storing information on a plurality of requests and processing the requests in parallel. Upon receipt of a memory access request, the MIB selects a request for a data block to be processed corresponding to the same set of a data block to be processed in response to the memory access request, and outputs a WAY assigned to the selected request to a replace-WAY selecting unit. The replace-WAY selecting unit excludes the WAY output from the MIB, and selects a WAY to be assigned to the memory access request based on a predetermined algorithm.

Abstract: A memory cache control arrangement for performing a coherency operation on a memory cache comprises a receive processor for receiving an address group indication for an address group comprising a plurality of addresses associated with a main memory. The address group indication may indicate a task identity and an address range corresponding to a memory block of the main memory. A control unit processes each line of a group of cache lines sequentially. Specifically it is determined if each cache line is associated with an address of the address group by evaluating a match criterion. If the match criterion is met, a coherency operation is performed on the cache line. If a conflict exists between the coherency operation and another memory operation the coherency means inhibits the coherency operation. The invention allows a reduced duration of a cache coherency operation. The duration is further independent of the size of the main memory address space covered by the coherency operation.

Abstract: A system and method for controlling access to an instance method on an instance-specific basis by intercepting an invocation of the instance method on an instance.

Abstract: In general, in one aspect, the disclosure describes an apparatus that includes a memory device having a plurality of memory cells. An inverter is used to invert data and tag information destined for the memory device. A register is used to capture the inverted data and tag information. A write inverted value logic is used to determine when to enable writing the inverted data and tag information from the register to the memory device. When inverted data and tag information is written to a memory cell the memory cell is invalidated.

Abstract: A cache memory processing system is disclosed that is coupled to a main memory and a processing unit. The cache memory processing system includes an input, a low order bit data path, a high order bit data path and an output. The input is for receiving input data that includes at least one low order input bit and at least one high order input bit. The low order bit data path is for processing the at least one low order input bit and providing at least one low order output bit. The high order bit data path for processing the at least one high order input bit and providing at least one high order output bit. The high order bit data path includes at least one exclusive or gate. The output is for providing the at least one low order output bit and the at least one high order output bit.

Abstract: Method and apparatus for building large memory-resident hash tables on general purpose processors. The hash table is broken into bands that are small enough to fit within the processor cache. A log is associated with each band and updates to the hash table are written to the appropriate memory-resident log rather than being directly applied to the hash table. When a log is sufficiently full, updates from the log are applied to the hash table insuring good cache reuse by virtue of false sharing of cache lines. Despite the increased overhead in writing and reading the logs, overall performance is improved due to improved cache line reuse.

Abstract: A method and apparatus for detecting a cache wrap condition in a computing environment having a processor and a cache. A cache wrap condition is detected when the entire contents of a cache have been replaced, relative to a particular starting state. A set-associative cache is considered to have wrapped when all of the sets within the cache have been replaced. The starting point for cache wrap detection is the state of the cache sets at the time of the previous cache wrap. The method and apparatus is preferably implemented in a snoop filter having filter mechanisms that rely upon detecting the cache wrap condition. These snoop filter mechanisms requiring this information are operatively coupled with cache wrap detection logic adapted to detect the cache wrap event, and perform an indication step to the snoop filter mechanisms. In the various embodiments, cache wrap detection logic is implemented using registers and comparators, loadable counters, or a scoreboard data structure.

Abstract: Extended translation look-aside buffers (eTLB) for converting virtual addresses into physical addresses are presented, the eTLB including, a physical memory address storage having a number of physical addresses, a virtual memory address storage configured to store a number of virtual memory addresses corresponding with the physical addresses, the virtual memory address storage including, a set associative memory structure (SAM), and a content addressable memory (CAM) structure; and comparison circuitry for determining whether a requested address is present in the virtual memory address storage, wherein the eTLB is configured to receive an index register for identifying the SAM structure and the CAM structure, and wherein the eTLB is configured to receive an entry register for providing a virtual page number corresponding with the plurality of virtual memory addresses.

Abstract: A cache module for a central processing unit has a cache control unit with an interface for a memory, a cache memory coupled with the control unit, wherein the cache memory has a plurality of cache lines, at least one cache line of the plurality of cache lines has an address tag bit field and an associated storage area for storing instructions or data, wherein the address tag bit field is readable and writeable and wherein the cache control unit is operable upon detecting that an address has been written to the address tag bit field to initiate a preload function in which instructions or data from the memory are loaded from the address into the at least one cache line.

Abstract: A data processor operable to process data said data processor comprising: a set associative cache divided into a plurality of cache ways and operable to store data processed by said data processor; a buffer operable to store a table comprising a plurality of mappings of pages of virtual addresses to pages of physical addresses for said data processor; a data store comprising a plurality of data entries each operable to store data for identifying an address of a memory location for each of a plurality of recent cache accesses, each of said plurality of data entries comprising a page index indicating a page in an address space, offset data indicating a location within said page and cache way data identifying a cache way of a cache storage location accessed by said cache access; wherein said data processor is operable in response to a cache access request comprising a virtual address indicating a memory location to access said table and said data store to determine whether said cache access request is to one of