Apple Inc.

Hewlett-packard Development Company, L.p.

John H Mylius

Daniel C Murray

Gerard Richard Williams

Jong-Suk Lee

Conrad Havluj Ziesler

Rohit Kumar

Suparn Vats

James B Keller

Pradeep Kanapathipillai

Andrew J Beaumont-Smith

Conrado Blasco-Allue

Kevin R Walker

Peter J Bannon

Stephan G Meier

Shih-Chieh Wen

Honkai Tam

Hari Kannan

Sandeep Kumar Gupta

Joel S Emer

Ramesh B Gunna

George Zacharias Chrysos

Toshinari Takayanagi

Bernard Joseph Semeria

Richard F Russo

Jung Wook Cho

Jason M Kassoff

Rajat Goel

Shyam Sundar

Karthik Rajagopal

Richard H Larson

Shyam Sundar Balasubramanian

Fang Liu

Toshi Takayanagi

Chuan-Hua Chang

Peter Soderquist

Conrade Blasco-Allue

Abhijit Radhakrishnan

Gerard R Williams Iii

Gerard R Williams

Gerard R Iii Williams

An integrated circuit may include multiple instances of a component (e.g. a processor) and a control circuit. The instances may be configured to operate in various modes. Some of the modes are incapable of presenting a worst-case load on the power supply. The control circuit may be configured to monitor the instances and detect the modes in which the instances are operating. Based on the monitoring, the control circuit may request to recover a portion of the voltage margin established for worst-case conditions in the instances.

Dynamic voltage margin recovery

An integrated circuit may include multiple instances of a component (e.g. a processor) and a control circuit. The instances may be configured to operate in various modes. Some of the modes are incapable of presenting a worst-case load on the power supply. The control circuit may be configured to monitor the instances and detect the modes in which the instances are operating. Based on the monitoring, the control circuit may request to recover a portion of the voltage margin established for worst-case conditions in the instances. If the instances are to change modes, they may be configured to request mode change from the control circuit. If the mode change causes an increase in the current supply voltage magnitude (e.g., to restore some of the recovered voltage margin), the control circuit may cause the restore and permit it to complete prior to granting the mode change.

An integrated circuit includes multiple instances of a component (e.g. a processor) and a control circuit. The instances may be configured to operate in various modes. Some of the modes are incapable of presenting a worst-case load on the power supply. The control circuit may be configured to monitor the instances and detect the modes in which the instances are operating. Based on the monitoring, the control circuit may request to recover a portion of the voltage margin established for worst-case conditions in the instances. If the instances are to change modes, they may be configured to request mode change from the control circuit. If the mode change causes an increase in the current supply voltage magnitude (e.g. to restore some of the recovered voltage margin), the control circuit may cause the restore and permit it to complete prior to granting the mode change.

Systems, apparatuses, and methods for retaining architected state for relatively frequent switching between sleep and active operating states are described. A processor receives an indication to transition from an active state to a sleep state. The processor stores a copy of a first subset of the architected state information in on-die storage elements capable of retaining storage after power is turned off. The processor supports programmable input/output (PIO) access of particular stored information during the sleep state. When a wakeup event is detected, circuitry within the processor is powered up again. A boot sequence and recovery of architected state from off-chip memory are not performed. Rather than fetch from a memory location pointed to by a reset base address register, the processor instead fetches an instruction from a memory location pointed to by a restored program counter of the retained subset of the architected state information.

Architected state retention for a frequent operating state switching processor

In an embodiment, an integrated circuit includes multiple instances of a component (e.g. a processor) and a control circuit. The instances may be configured to operate in various modes. Some of the modes are incapable of presenting a worst-case load on the power supply. The control circuit may be configured to monitor the instances and detect the modes in which the instances are operating. Based on the monitoring, the control circuit may request to recover a portion of the voltage margin established for worst-case conditions in the instances. If the instances are to change modes, they may be configured to request mode change from the control circuit. If the mode change causes an increase in the current supply voltage magnitude (e.g. to restore some of the recovered voltage margin), the control circuit may cause the restore and permit it to complete prior to granting the mode change.

Systems, apparatuses, and methods for reaching power targets across different clock domains are described. In various embodiments, a first processor complex and a second processor complex operate while powered by a same, single power plane, but with respective clock domains. When a request is detected to change an operating mode of a particular core from one of the processor complexes to an operating mode which does not provide the worst-case power supply load on the single power plane, an amount of voltage margin to recover from the operational voltage is determined based on the second operating mode prior to granting the request and based on each other core in the complexes operating in respective current operating modes. An operational voltage less the determined voltage margin to recover is assigned to the processor complexes while different clock frequencies are assigned to the processor complexes.

Single power plane dynamic voltage margin recovery for multiple clock domains

A system and method for reducing the latency of load operations. A register rename unit within a processor determines whether a decoded load instruction is eligible for conversion to a zero-cycle load operation. If so, control logic assigns a physical register identifier associated with a source operand of an older dependent store instruction to the destination operand of the load instruction. Additionally, the register rename unit marks the load instruction to prevent it from reading data associated with the source operand of the store instruction from memory. Due to the duplicate renaming, this data may be forwarded from a physical register file to instructions that are younger and dependent on the load instruction.

Zero cycle load

Methods and processors for managing load-store dependencies in an out-of-order instruction pipeline. A load store dependency predictor includes a table for storing entries for load-store pairs that have been found to be dependent and execute out of order. Each entry in the table includes hashed values to identify load and store operations. When a load or store operation is detected, the PC and an architectural register number are used to create a hashed value that can be used to uniquely identify the operation. Then, the load store dependency predictor table is searched for any matching entries with the same hashed value.

Load-store dependency predictor PC hashing

A system and method for reducing the latency of data move operations. A register rename unit within a processor determines whether a decoded move instruction is eligible for a zero cycle move operation. If so, control logic assigns a physical register identifier associated with a source operand of the move instruction to the destination operand of the move instruction. Additionally, the register rename unit marks the given move instruction to prevent it from proceeding in the processor pipeline. Further maintenance of the particular physical register identifier may be done by the register rename unit during commit of the given move instruction.

Zero cycle move

Techniques are disclosed relating to completion of load and store instructions in a weakly-ordered memory model. In one embodiment, a processor includes a load queue and a store queue and is configured to associate queue information with a load instruction in an instruction stream. In this embodiment, the queue information indicates a location of the load instruction in the load queue and one or more locations in the store queue that are associated with one or more store instructions that are older than the load instruction. The processor may determine, using the queue information, that the load instruction does not conflict with a store instruction in the store queue that is older than the load instruction. The processor may remove the load instruction from the load queue while the store instruction remains in the store queue. The queue information may include a wrap value for the load queue.

Completing load and store instructions in a weakly-ordered memory model

A system and method for efficiently reducing the latency of initializing registers. A register rename unit within a processor determines whether prior to an execution pipeline stage it is known a decoded given instruction writes a particular numerical value in a destination operand. An example is a move immediate instruction that writes a value of 0 in its destination operand. Other examples may also qualify. If the determination is made, a given physical register identifier is assigned to the destination operand, wherein the given physical register identifier is associated with the particular numerical value, but it is not associated with an actual physical register in a physical register file. The given instruction is marked to prevent it from proceeding to an execution pipeline stage. When the given physical register identifier is used to read the physical register file, no actual physical register is accessed.

Optimizing register initialization operations

A free list in processor includes multiple banks for indicating availability of register identifiers used for register renaming. A register rename unit receives one or more destination architectural registers to rename with physical register identifiers. Responsive to determining the multiple banks within the free list are unbalanced with available physical register identifiers, one or more returning physical register identifiers are assigned to the destination architectural registers before assigning any physical register identifiers from any bank of the multiple banks with a lowest number of available physical register identifiers. A returning physical register identifier is a physical register identifier that is available again for assignment to a destination architectural register but not yet indicated in the free list as available. Each of the banks includes a single bit width decoded vector for indicating availability of given physical register identifiers.

System and method for register renaming with register assignment based on an imbalance in free list banks

In an embodiment, a processor includes a multi-level dispatch circuit configured to supply operations for execution by multiple parallel execution pipelines. The multi-level dispatch circuit may include multiple dispatch buffers, each of which is coupled to multiple reservation stations. Each reservation station may be coupled to a respective execution pipeline and may be configured to schedule instruction operations (ops) for execution in the respective execution pipeline. The sets of reservation stations coupled to each dispatch buffer may be non-overlapping. Thus, if a given op is to be executed in a given execution pipeline, the op may be sent to the dispatch buffer which is coupled to the reservation station that provides ops to the given execution pipeline.

Multi-level dispatch for a superscalar processor

Growing community of inventors

Gilroy, CA, United States of America

John H Mylius