International Business Machines Corporation

David Allen Hrusecky

Robert Allen Cordes

Brian William Thompto

Sundeep Chadha

Hung Qui Le

Dung Q Nguyen

Bryan J Lloyd

Elizabeth A McGlone

Albert James Van Norstrand, Jr

Kimberly Marie Fernsler

Sheldon Bernard Levenstein

Jentje Leenstra

Chuck Hong Ngai

Dennis P Cheney

Jennifer L Molnar

Kenneth Lundy Ward

David A Campbell

Salma Ayub

Francesco A Campisano

Brian Chen

Bruce Joseph Ronchetti

Miles Robert Dooley

Scott Bruce Frommer

Samuel David Kirchhoff

Guy L Guthrie

Anthony Saporito

Richard James Eickemeyer

Susan Elizabeth Eisen

Maarten Jakob Boersma

Jose Angel Paredes

Shih-Hsiung Stephen Tung

Michael Thomas Vaden

Christopher M Mueller

Ronald S Svec

A James Van Norstrand, Jr

Rachel Flood

Jeffrey A Stuecheli

Stamatis Vassiliadis

Phillip G Williams

Rolf Sautter

Charles Francis Marino

Dwain Alan Hicks

David Scott Ray

James Edward Phillips

George W Rohrbaugh, Iii

Michael Putrino

Wolfgang Penth

Michael James Mack

Werner Juchmes

Steven Bradford Herndon

Stefan Buettner

Roger Sherman Rutter

Daniel J Buerkle

Christian Gerhard Zoellin

John William Urda

Mihailo M Stojancic

A computer system, processor, programming instructions and/or method for managing operations of a gather buffer for a processor core load storage unit. The processor core includes a processing pipeline having one or more execution units for processing unaligned load instructions that executes in two phases to satisfy. A buffer storage element is provided having a plurality of entries for temporarily collecting partial writeback results retrieved from the memory that are associated with first phase accesses for each of a plurality of unaligned load instructions. An associated logic controller device tracks two parts of the unaligned load to be gathered at independent times, wherein said partial result stored at said buffer storage element comprises a first part of an unaligned load. The second phase load access for the same instruction is independently accessed and later merged with first part of the load data at byte granularity to satisfy the load.

Gather buffer management for unaligned and gather load operations

An execution unit circuit for use in a processor core provides efficient use of area and energy by reducing the per-entry storage requirement of a load-store unit issue queue. The execution unit circuit includes a recirculation queue that stores the effective address of the load and store operations and the values to be stored by the store operations. A queue control logic controls the recirculation queue and issue queue so that that after the effective address of a load or store operation has been computed, the effective address of the load operation or the store operation is written to the recirculation queue and the operation is removed from the issue queue, so that address operands and other values that were in the issue queue entry no longer require storage. When a load or store operation is rejected by the cache unit, it is subsequently reissued from the recirculation queue.

Parallel slice processor having a recirculating load-store queue for fast deallocation of issue queue entries

Technology for fusing certain load instructions and compare-immediate instructions in a computer processor having a load-store architecture with respect to transferring data between memory and registers of the computer processor. In some embodiments the load and compare-immediate instructions are consecutive. In some embodiments, the instructions are only merged if: (i) the respective RA and RT fields of the two instructions match; (ii) the immediate field of the compare-immediate instruction has a certain value, or falls within a range of certain values; and/or (iii) the instructions are received in a consecutive manner.

Microprocessor that fuses load and compare instructions

System includes at least one computer processor having a load store execution unit (LSU) for processing load and store instructions, wherein the LSU includes (a) a store queue having a plurality of entries for storing data, each store queue entry having a data field for storing the data, the data field having a width for storing the data; and (b) a gather buffer for holding data, wherein the processor is configured to: process oversize data larger than the width of the data field of the store queue, and process an oversize load instruction for oversize data by executing two passes through the LSU, a first pass through the LSU configured to store a first portion of the oversize data in the gather buffer and a second pass through the LSU configured to merge the first portion of the oversize data with a second portion of the oversize data.

Handling oversize store to load forwarding in a processor

A computer system, processor, and/or load-store unit has a data cache for storing data, the data cache having a plurality of entries to store the data, each data cache entry addressed by a row and a Way, each data cache row having a plurality of the data cache Ways; a first Address Directory organized and arranged the same as the data cache where each first Address Directory entry is addressed by a row and a Way where each row has a plurality of Ways; a store reorder queue for tracking the store instructions; and a load reorder queue for tracking load instruction. Each of the load and store reorder queues having a Way bit field, preferably less than six bits, for identifying the data cache Way and/or a first Address Directory Way where the Way bit field acts as a proxy for a larger address, e.g. a real page number.

Tracking load and store instructions and addresses in an out-of-order processor

Translation lookaside buffer (TLB) invalidation using virtual addresses is provided. A cache is searched for a virtual address matching the input virtual address. Based on a matching virtual address in the cache, the corresponding cache entry is invalidated. The load/store queue is searched for a set and a way corresponding to the set and the way of the invalidated cache entry. Based on an entry in the load/store queue matching the set and the way of the invalidated cache entry, the entry in the load/store queue is marked as pending. Indicating a completion of the TLB invalidate instruction is delayed until all pending entries in the load/store queues are complete.

Dynamic translation lookaside buffer (TLB) invalidation using virtually tagged cache for load/store operations

A system and method of stopping program execution includes tagging an entry in a virtual cache with an indicator bit where the virtual address of the entry corresponds to a virtual address range in a break point register, in response to a second virtual cache data access demand matching the entry tagged with the indicator bit, determining whether the second data access demand matches the virtual address range of the breakpoint register, and in response to the second data access demand matching the virtual address range of the break point register, flagging an exception and stopping execution of the program. In an embodiment, the method or system enters a slow-mode in response to the second data access demand matching the virtual cache entry with the indicator bit, and performs a full comparison between the second data access demand and the break point register virtual address range.

Virtual cache mechanism for program break point register exception handling

Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

Handling unaligned load operations in a multi-slice computer processor

Preventing hazard flushes in an instruction sequencing unit of a multi-slice processor including receiving a load instruction in a load reorder queue, wherein the load instruction is an instruction to load data from a memory location; subsequent to receiving the load instruction, receiving a store instruction in a store reorder queue, wherein the store instruction is an instruction to store data in the memory location; determining that the store instruction causes a hazard against the load instruction; preventing a flush of the load reorder queue based on a state of the load instruction; and re-executing the load instruction.

Preventing hazard flushes in an instruction sequencing unit of a multi-slice processor

Techniques are disclosed for receiving an instruction for processing data that includes a plurality of sectors. A method includes decoding the instruction to determine which of the plurality of sectors are needed to process the instruction and fetching at least one of the plurality of sectors from memory. The method includes determining whether each sector that is needed to process the instruction has been fetched. If all sectors needed to process the instruction have been fetched, the method includes transmitting a sector valid signal and processing the instruction. If all sectors needed to process the instruction have not been fetched, the method includes blocking a data valid signal from being transmitted, fetching an additional one or more of the plurality of sectors until all sectors needed to process the instruction have been fetched, transmitting a sector valid signal, and reissuing and processing the instruction using the fetched sectors.

Fetched data in an ultra-short piped load store unit

Growing community of inventors

Cedar Park, TX, United States of America

David Allen Hrusecky