Apple Inc.

Advanced Micro Devices Corporation

Globalfoundries Inc.

David Edward Kroesche

Brett Stanley Feero

Christopher Colletti

Michael T Clark

Jonathan Y Tong

Ronald P Hall

Benjamin T Sander

Sreevathsa Ramachandra

Thang M Tran

Mitchell K Alsup

Brian D McMinn

Edward J McLellan

David James Williamson

James Nolan Hardage

Todd Alan Venton

Michael Lance Karm

Kelvin Domnic Goveas

Michael A Filippo

Andrew McBride

Karthikeyan Muthusamy

Arun Radhakrishnan

Swamy Punyamurtula

Steven Beigelmacher

Matthew C Stone

Jonathan Ying Fai Tong

Gagan Anand

So Min Song

Justin M Deinlein

A processor may include an instruction pipeline that executes program instructions in-order according to a program order. During operation, the instruction pipeline may detect that data is missing for a first instruction. In response, the instruction pipeline may send a request to load the missing data for the first instruction. However, the instruction pipeline may not necessarily stall operation to wait for the missing data to be loaded. Instead, the instruction pipeline may continue executing instructions subsequent to the first instruction. During the continued execution, the instruction pipeline may detect that data is missing for a second instruction, and send a request to load the missing data for the second instruction. The instruction pipeline may continue such operation until it determines that a condition occurs that prevents the continued execution. When the condition occurs, the instruction pipeline may stop the continued execution, and then re-execute the first instruction.

Processor implementing parallel in-order execution during load misses

Techniques are disclosed relating to managing storage array invalidations. A computer system may comprise a processor core configured to operate in an idle state and operate in a run state in which the processor core executes instructions. The computer system may further comprise a power management circuit that is configured to receive, while the processor core is in the idle state, a set of invalidation requests directed to the processor core to invalidate a set of entries of a storage array of the processor core. The power management circuit may store invalidation information indicative of the set of invalidation requests. The power management circuit may determine that the processor core has received a request to transition to the run state. Prior to the processor core operating in the run state, the power management circuit may invalidate the set of entries of the storage array based on the invalidation information.

Storage array invalidation maintenance

A processor configured for real-time transaction processing is disclosed. A processor circuit includes configuration registers that designate a first range of physical memory addresses as reserved for real-time memory requests and a second, non-overlapping range of physical memory addresses that are shared between real-time and non-real-time memory requests. In response to determining that a memory request is associated with an address in the first range, the processor tags the request as a real-time request. The configuration registers may also store information designating portions of one or more cache memories and one or more buffers as being reserved for real-time memory requests. During arbitration, real-time memory requests are given priority over older, non-real-time memory requests.

Real-time processing in computer systems

A processor with reduced interrupt latency is disclosed. An apparatus includes a processor core and a cache subsystem having a cache controller and a cache. The processor core is configured to submit, to the cache controller, requests for access to the cache, wherein a given request for access to the cache specifies whether the given request is abandonable or non-abandonable in an event of an interrupt request. In response to a particular interrupt request, the processor core may provide an indication to cause the cache controller to abandon requests for access to the cache identified as abandonable. After receiving an acknowledgement from the cache controller that the abandonable requests have been abandoned, the processor core may begin execution of an interrupt handler in order to service the interrupt request.

Processor with reduced interrupt latency

A system and method for efficiently handling maintenance requests among multiple processors. In various embodiments, a given processor of multiple processors receives a maintenance request. If maintenance requests are not currently being blocked, then the given processor determines a type of the maintenance request and updates one or more maintenance type counters based on the type. If one or more counters exceed a threshold, an indication is generated specifying maintenance requests received at a later time are to be held. The received maintenance request is processed. Different types of maintenance requests are used for invalidating entries in the instruction cache, for invalidating entries in a TLB and for synchronizing page table updates. Afterward, software applications continue processing. Forward progress of the software applications is measured using one or more metrics. If forward progress has been achieved, then one or more maintenance type counters are reset.

Method to ensure forward progress of a processor in the presence of persistent external cache/TLB maintenance requests

An apparatus includes a control circuit and a cache memory with a plurality of regions. The control circuit receives a first and a second access request to access the cache memory. In response to determining that the first access request is from a particular processor core, and that the first access request is associated with a particular cache line in the cache memory, the control circuit stores the first access request in a cache access queue. In response to a determination that the second access request is received from a functional circuit, and that the second access request is associated with a range of a memory address space mapped to a subset of the plurality of regions, the control circuit stores the second access request in a memory access queue. The control circuit arbitrates access to the cache memory circuit between the first access request and the second access request.

Using cache memory as RAM with external access support

Various embodiments of a method and apparatus for flushing a cache are disclosed. In a system, a cache memory is accessible by an execution circuit. The execution circuit executes instructions and may utilize data and/or instructions stored in the cache. A flush circuit is also coupled to the cache. Responsive to execution of a power down instruction by the execution circuit, the flush circuit performs a cache flush. If a control state is asserted in a control register, the flush circuit generates a dummy event upon completing the cache flush. Responsive to generating the dummy event, a processor core that includes the execution circuit is inhibited from being powered down.

Cache flush method and apparatus

A method of implementing a mask load or mask store instruction by a processor is provided. The method may include receiving the mask load or mask store instruction, a location of a memory operand and a location of corresponding mask bits associated with the memory operand, breaking the received memory operand into a plurality of sub-operands and executing the mask load or mask store instruction on each of the plurality of sub-operands using a fastpath operation or using microcode, wherein the respective mask load or mask store instruction loads or stores each of the plurality of sub-operands based upon the corresponding mask bits.

Processor and method implemented by a processor to implement mask load and store instructions

A method includes storing a first data to a first portion of a storage location of a storage component of a processing device in association with a first store operation and obtaining a second data from the storage location, the second data being stored at the storage location prior to the first data. The method further includes determining whether the storage location has a bit error at second portion of the storage location different from the first portion based on the second data obtained from the storage location. The method additionally includes storing a third data to a second portion of the storage location in response to determining the storage location has a bit error at the second portion, wherein the third data is to correct the bit error.

Parallel instruction processing and operand integrity verification

A method of controlling write operations to a non-renamed register space includes receiving a write operation to a given register within the non-renamed register space. The method also includes determining whether a pending write operation to the given register exists. In response to determining that the pending write operation to the given register exists, the method includes blocking the write operation to the given register from being scheduled. However, in response to determining that the pending write operation to the given register does not exist, the method includes allowing the write operation to the given register to be scheduled. Further, if the pending write operation to the given register does not exist, the method includes allowing a subsequent write operation to a different register within the non-renamed register space to be scheduled.

Controlling writes to non-renamed register space in an out-of-order execution microprocessor

A microprocessor is configured to provide port arbitration in a register file. The microprocessor includes a plurality of functional units configured to collectively operate on a maximum number of operands in a given execution cycle, and a register file providing a number of read ports that is insufficient to provide the maximum number of operands to the plurality of functional units in the given execution cycle. The microprocessor also includes an arbitration logic coupled to allocate the read ports of the register file for use by selected functional units during the given execution cycle.

Apparatus and method for port arbitration in a register file on the basis of functional unit issue slots

A microprocessor employing a fixed position dispatch unit. The microprocessor includes a plurality of execution units each corresponding to an issue position and configured to execute a common subset of instructions. At least a first one of the execution units includes extended logic for executing a designated instruction that others of the execution units may be incapable of executing. The microprocessor also includes a plurality of decoders coupled to the plurality of execution units. The plurality of decoders may provide positional information to cause the designated instruction to be routed to the first execution unit. Further, the microprocessor includes a dispatch control unit configured to dispatch during a dispatch cycle, the designated instruction for execution by the first execution unit based upon the positional information. The dispatch control unit may further dispatch one or more instructions within the common subset of instructions during the same dispatch cycle.

Microprocessor employing a fixed position dispatch unit

A branch prediction unit includes a branch prediction entry corresponding to a group of contiguous instruction bytes. The branch prediction entry stores branch predictions corresponding to branch instructions within the group of contiguous instruction bytes. Additionally, the branch prediction entry stores a set of branch selectors corresponding to the group of contiguous instruction bytes. The branch selectors identify which branch prediction is to be selected if the corresponding byte (or bytes) is selected by the offset portion of the fetch address. Still further, a predicted branch selector is stored. The predicted branch selector is used to select a branch prediction for forming the fetch address. In parallel, a selected branch selector is selected from the set of branch selectors. The predicted branch selector is verified using the selected branch selector. If the selected branch selector and the predicted branch selector mismatch, the correct branch prediction is generated and the predicted branch selector is updated to indicate the selected branch selector.

Growing community of inventors

Austin, TX, United States of America

David Edward Kroesche