International Business Machines Corporation

Motorola Corporation

Pei-Chun Peter Liu

Rajinder Paul Singh

Brad B Beavers

Chih-Jui Peng

Lew G Chua-Eoan

Dwain Alan Hicks

Shih-Hsiung Stephen Tung

Song C Kim

Kin Shing Chan

Chua-Eoan Lew

A cache has an array for holding data or instruction values, a buffer connected to the array, and means for accessing the buffer to retrieve a value for a processing unit. The accessing means uses wires having a pitch which is substantially equal to a wire pitch of the cache array. Multiplexers can be used with a plurality of such buffers to create a common output path. The cache can be interleaved, with the array being a first subarray, and the buffer being a first buffer, and further comprising a second subarray and a second buffer, wherein the first and second buffers separate the first and second subarrays. The invention can be applied to a store-back buffer as well as a reload buffer.

Integrated cache buffers

The present invention is directed to an apparatus for precharging complementary data circuits. The apparatus comprises two hold circuits, one for storing the data and the other for storing its complement. A signal for initiates precharging the hold circuits to the same signal level, where the signal for initiating the precharging of the hold circuits is dependent on the hold circuits' outputs.

Dynamic circuit for capturing data with wide reset tolerance

A fully associative address translator which includes a number of entries, each of said number of entries translating a received effective address into a real address, each received effective address including a segment identifier and a page identifier. Each of the entries within the fully associative address translator includes a first translation from an effective address segment identifier into a virtual address segment identifier and a second translation from a virtual address page identifier to a real address page identifier. A first valid bit cell is provided for storing a validity bit which indicates the validity of the first translation from the effective address segment identifier to the virtual address segment identifier and a second valid bit cell is also provided for storing a validity bit indicating the validity of the second translation from the virtual address page identifier to the real address page identifier wherein a process context switch will invalidate only a portion of each of the entries, thereby reducing the miss penalty associated with a context switch.

Fully associative address translation buffer having separate segment and

A CAM/SRAM structure (44) performs address translations that are compatible with a segmentation/paging addressing scheme yet require only a single look-up step. Each entry in the effective-to-real-address-translator (ERAT) has two CAM fields (ESID, EPI) that independently compare an input segment identifier and an input page identifier to a stored segment identifier and a stored page identifier, respectively. The ERAT outputs a stored real address field (DATA) associated with a stored segment-stored page pair if both comparisons are equivalent. The ERAT can invalidate stored translations on the basis of segment or page granularity by requiring either a segment or a page CAM field match, respectively, during an invalidate operation.

Single array address translator with segment and page invalidate ability

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Austin, TX, United States of America

Pei-Chun Peter Liu