Advanced Micro Devices Corporation

Ati Technologies Ulc

Michael Estlick

Erik D Swanson

Jay E Fleischman

Sneha V Desai

Eric Dixon

Michael Christopher Sedmak

Kevin Altair Hurd

John M King

Arun A Nair

Todd Baumgartner

Theodore Carlson

Gabriel H Loh

Yasuko Eckert

Bradford Michael Beckmann

Russell J Schreiber

Emil Talpes

Debjit Das Sarma

Krishnan V Ramani

Kelvin Domnic Goveas

Kai Troester

Keith Allen Kasprak

Michael L Golden

John Kelley

Eric W Busta

Magiting M Talisayon

Scott Thomas Bingham

Mark M Gibson

Hanbing Liu

James A Wingfield

Brian M Lay

Patrick Michael Lowry

Donglin Ji

Robert Weidner

Sree Harsha Kosuru

Anilkumar Ranganagoudra

Sean M O′Mullan

Chun Liu

Robert E Weidner

Ruchir Dalal

Richard McGowen, Ii

A coprocessor such as a floating-point unit includes a pipeline that is partitioned into a first portion and a second portion. A controller is configured to provide control signals to the first portion and the second portion of the pipeline. A first physical distance traversed by control signals propagating from the controller to the first portion of the pipeline is shorter than a second physical distance traversed by control signals propagating from the controller to the second portion of the pipeline. A scheduler is configured to cause a physical register file to provide a first subset of bits of an instruction to the first portion at a first time. The physical register file provides a second subset of the bits of the instruction to the second portion at a second time subsequent to the first time.

Differential pipeline delays in a coprocessor

An approach is provided for implementing register based single instruction, multiple data (SIMD) lookup table operations. According to the approach, an instruction set architecture (ISA) can support one or more SIMD instructions that enable vectors or multiple values in source data registers to be processed in parallel using a lookup table or truth table stored in one or more function registers. The SIMD instructions can be flexibly configured to support functions with inputs and outputs of various sizes and data formats. Various approaches are also described for supporting very large lookup tables that span multiple registers.

Register based SIMD lookup table operations

The disclosed system may include a processor configured to detect that a data unit size for an instruction is smaller than a register. The processor may allocate a first portion of the register to the instruction in a manner that leaves a second portion of the register available for allocating to an additional instruction. The processor may also track the register as a split register. Various other methods, systems, and computer-readable media are also disclosed.

Split register list for renaming

A data processing system includes a vector data processing unit that includes a shared scheduler queue configured to store in a same queue, at least one entry that includes at least a mask type instruction and another entry that includes at least a vector type instruction. Shared pipeline control logic controls a vector data path or a mask data path, based a type of instruction picked from the same queue. In some examples, at least one mask type instruction and the at least one vector type instruction each include a source operand having a corresponding shared source register bit field that indexes into both a mask register file and a vector register file. The shared pipeline control logic uses a mask register file or a vector register file depending on whether bits of the shared source register bit field identify a mask source register or a vector source register.

Methods and apparatus for providing mask register optimization for vector operations

Methods, systems, and apparatuses provide support for allowing thread forward progress in a processing system and that improves quality of service. One system includes a processor; a bus coupled to the processor; a memory coupled to the processor via the bus; and a floating point unit coupled to the processor via the bus, wherein floating point unit comprises hardware control logic operative to: store for each thread, by a scheduler of the floating point unit, a counter; increase, by the scheduler, a value of the counter for each thread corresponding to a thread when at least one source ready operation exist for the thread; compare, by the scheduler, the value of the counter to a predetermined threshold; and make other threads ineligible to be picked by the scheduler when the counter is greater than or equal to the predetermined threshold.

Thread forward progress and/or quality of service

A processor includes a plurality of execution pipes and a distributed scheduler coupled to the plurality of execution pipes. The distributed scheduler includes a first queue to buffer instruction operations from a front end of an instruction pipeline of the processor and a plurality of second queues, wherein each second queue is to buffer instruction operations allocated from the first queue for a corresponding separate subset of execution pipes of the plurality of execution pipes. The distributed scheduler further includes a queue controller to select an allocation mode from a plurality of allocation modes based on whether at least one indicator of an imbalance at the distributed scheduler is detected, and further to control the distributed scheduler to allocate instruction operations from the first queue among the plurality of second queues in accordance with the selected allocation mode.

Distributed scheduler providing execution pipe balance

In some implementations, a processor includes a plurality of parallel instruction pipes, a register file includes at least one shared read port configured to be shared across multiple pipes of the plurality of parallel instruction pipes. Control logic controls multiple parallel instruction pipes to read from the at least one shared read port. In certain examples, the at least one shared register file read port is coupled as a single read port for one of the parallel instruction pipes and as a shared register file read port for a plurality of other parallel instruction pipes.

Apparatus and methods employing a shared read post register file

An integrated circuit includes one or more processing units that execute instructions that employ a register file, control logic creates a pre-startup register free list, prior to normal operation of at least one of the processing units, that includes a list of registers devoid of defective registers. In some implementations, no column and row repair information is provided to register file repair logic. In certain examples, the register file is configured as a repair-less register file. During normal operation of the one or more processing units, the integrated circuit employs the pre-startup register free list to select registers in a register file for the executing instructions. Associated methods are also presented.

Methods and apparatus for managing register free lists

A processor includes a load/store unit and an execution pipeline to execute an instruction that represents a single-instruction-multiple-data (SIMD) operation, and which references a memory block storing operand data for one or more lanes of a plurality of lanes and a mask vector indicating which lanes of a plurality of lanes are enabled and which are disabled for the operation. The execution pipeline executes an instruction in a first execution mode unless a memory fault is generated during execution of the instruction in the first execution mode. In response to the memory fault, the execution pipeline re-executes the instruction in a second execution mode. In the first execution mode, a single load operation is attempted to access the memory block via the load/store unit. In the second execution mode, a separate load operation is performed by the load/store unit for each enabled lane of the plurality of lanes prior to executing the SIMD operation.

Masked multi-lane instruction memory fault handling using fast and slow execution paths

An apparatus includes a plurality of load buses and a load store unit that includes a plurality of load ports to access the plurality of load buses. The load store unit performs a gather operation to concurrently gather a plurality of subsets of data from a memory via the plurality of load buses in a first mode. The apparatus also includes a register that is partitioned into a plurality of portions to hold the plurality of subsets of data provided by the load store unit. The load store unit ignores exceptions or faults while performing the gather operation in the first mode and transitions to a second mode in response to an exception or fault. Two lanes are dispatched to concurrently perform the gather operation per clock cycle in the first mode and a single lane is dispatched to perform the gather operation per clock cycle in the second mode.

Multi-modal gather operation

A processor includes a register file and control logic that detects multiple different sets of sequential zero bits of a register in the register file, wherein each of the multiple different sets has a bit length that corresponds to a partial instruction width and operates at a first partial instruction width or a second partial instruction width with the register file depending on number of sets of zero bits detected in the register. In certain examples, the control logic causes operating at first instruction width that avoids merging of a first bit length of data in the register and operating at the second instruction width that avoids merging of a second bit length of data in the register. In some examples, a register rename map table incudes multiple zero bits that identify the detected multiple different sets of bits of sequential zeros.

Method and apparatus for executing vector instructions with merging behavior

A pipeline includes a first portion configured to process a first subset of bits of an instruction and a second portion configured to process a second subset of the bits of the instruction. A first clock mesh is configured to provide a first clock signal to the first portion of the pipeline. A second clock mesh is configured to provide a second clock signal to the second portion of the pipeline. The first and second clock meshes selectively provide the first and second clock signals based on characteristics of in-flight instructions that have been dispatched to the pipeline but not yet retired. In some cases, a physical register file is configured to store values of bits representative of instructions. Only the first subset is stored in the physical register file in response to the value of the zero high bit indicating that the second subset is equal to zero.

Clock mesh-based power conservation in a coprocessor based on in-flight instruction characteristics

A processor includes a front-end with an instruction set that operates at a first bit width and a floating point unit coupled to receive the instruction set in the processor that operates at the first bit width. The floating point unit operates at a second bit width and, based upon a bit width assessment of the instruction set provided to the floating point unit, the floating point unit employs a shadow-latch configured floating point register file to perform bit width reconfiguration. The shadow-latch configured floating point register file includes a plurality of regular latches and a plurality of shadow latches for storing data that is to be either read from or written to the shadow latches. The bit width reconfiguration enables the floating point unit that operates at the second bit width to operate on the instruction set received at the first bit width.

Bit width reconfiguration using a shadow-latch configured register file

A processor employs a set of bits to indicate values of portions of registers of a register file. In response to a specified instruction indicating an expected change of instruction types to be executed, the processor sets one or more of the bits and, for subsequent instructions, interprets corresponding portions of the registers as having a specified value (e.g., zero). By employing the set of bits to set the values of the register portions, rather than setting the individual portions of the registers to the specified value, the processor conserves processor resources (e.g., power) when the processor transitions between executing instructions of different types.

Setting values of portions of registers based on bit values

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Fort Collins, CO, United States of America

Michael Estlick