Hewlett-packard Development Company, L.P.

Hewlett-packard Company

Henry Yu

Curtis R McAllister

Robert C Douglas

Gary Belgrave Gostin

Michael K Dugan

Mark A Heap

Terry C Huang

Nolan David Sharp

A memory system and method for processing a data structure comprising a plurality of data bits representing a line of memory, wherein the data bits are divided into a plurality of data chunks, each of the data chunks including at least an error correction code portion and a data portion; and a first chunk of said plurality of data chunks having a tag portion, wherein said tag portion includes tag information for the entire line of memory, and wherein subsequent ones of said data chunks do not include tag information.

Arrangement of data within cache lines so that tags are first data received

An apparatus and method for performing speculative directory cache tag updates for read accesses to memory is herein disclosed. A control unit for performing tag updates is coupled between the memory controller and the memory bank in a multiprocessor system that employs a directory-based coherency protocol. The control unit transmits data read from the memory bank to the memory controller while calculating the updated tag that it then writes back to the memory bank. In this manner, the memory bank busy time and memory bus traffic are reduced thereby improving the overall performance of a memory access.

Apparatus and method for performing speculative cache directory tag updates

An application specific integrated circuit (ASIC) and method of manufacture. The ASIC includes a substrate layer, at least one metal layer and an operational block. The metal layer is formed above the substrate layer. The operational block is formed in the substrate layer and the metal layer, and is definable by a two-dimensional boundary. The operational block includes a plurality of operational logic gates, a first subgroup of spare logic gates, a second subgroup of spare logic gates, operational wiring and spare gate wiring. The operational logic gates, the first subgroup and the second subgroup are formed on the substrate layer, with the first subgroup being spaced from the second subgroup. The operational wiring is routed into the metal layer and interconnects the operational logic gates to configure the operational block to perform a desired operation. The spare gate wiring is similarly routed into the metal layer. The spare gate wiring is separate from the operational wiring, and connects at least one of the first subgroup logic gates to at least one of the second subgroup logic gates. In a preferred embodiment, a plurality of metal layers are provided, and a spacing between the subgroups dictates that the spare gate wiring, as formed by an automatic routing tool, extends to the outer metal layers where it is accessible by a focused ion beam device.

Application specific integrated circuit with spaced spare logic gate subgroups and method of fabrication

A memory system includes a main memory controller supplying data in response to transactions received by the main memory controller. A plurality of modules each include a cache memory for storing data supplied by the main memory controller. The modules request data from the main memory controller by sending module generated transactions to the main memory controller. A cache tag array includes a cache tag corresponding to each data line stored in memory, there being a one-to-one correspondence between the cache tags and the data lines. The data lines together with their associated cache tags are combined and arranged in a plurality of sequential data chunks, the cache tags included in an initial portion of the data chunks (i.e, a first sequence of bits) followed by inclusion of the data lines in a subsequent portion of the data chunks (i.e., the usable bit positions following inclusion of all of the cache tag bits.) Each of the chunks may further include appropriate ECC bits. By this arrangement, all of the cache tags are transferred between the main memory controller and the plurality of modules prior to transfer of the bits constituting the data lines so that any coherency operations may be initiated without waiting to receive the remaining data of the data line.

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San Jose, CA, United States of America

Henry Yu