公开(公告)号：US20210019148A1

公开(公告)日：2021-01-21

申请号：US17041312

申请日：2019-03-14

Applicant: Arm Limited

Inventor： Ian Michael CAULFIELD ,  Peter Richard GREENHALGH ,  Frederic Claude Marie PIRY ,  Albin Pierrick TONNERRE

IPC: G06F9/38 ,  G06F12/0875

Abstract: Examples of the present disclosure relate to an apparatus comprising execution circuitry to execute instructions defining data processing operations on data items. The apparatus comprises cache storage to store temporary copies of the data items. The apparatus comprises prefetching circuitry to a) predict that a data item will be subject to the data processing operations by the execution circuitry by determining that the data item is consistent with an extrapolation of previous data item retrieval by the execution circuitry, and identifying that at least one control flow element of the instructions indicates that the data item will be subject to the data processing operations by the execution circuitry; and b) prefetch the data item into the cache storage.

公开(公告)号：US20170139716A1

公开(公告)日：2017-05-18

申请号：US14944803

申请日：2015-11-18

Applicant: ARM Limited

Inventor： Ian Michael CAULFIELD ,  Max John BATLEY ,  Chiloda Ashan Senarath PATHIRANE

IPC: G06F9/38

CPC classification number: G06F9/3851

Abstract: A processing pipeline for processing instructions with instructions from multiple threads in flight concurrently may have control circuitry to detect a stalling event associated with a given thread. In response, at least one instruction of the given thread may be flushed from the pipeline, and the control circuitry may trigger fetch circuitry to reduce a fraction of the fetched instructions which are fetched from the given thread. A mechanism is also described to determine when to trigger a predetermined action when a delay in accessing information becomes greater than a delay threshold, and to update the delay threshold based on a difference between a return delay when the information is returned from the storage circuitry and the delay threshold.

公开(公告)号：US20170132010A1

公开(公告)日：2017-05-11

申请号：US14938285

申请日：2015-11-11

Applicant: ARM LIMITED

Inventor： Vladimir VASEKIN ,  Ian Michael CAULFIELD ,  Chiloda Ashan Senarath PATHIRANE

IPC: G06F9/38

CPC classification number: G06F9/3855 ,  G06F9/384

Abstract: An apparatus for data processing and a method of data processing are provided. Data processing operations are performed in response to instructions which reference architectural registers using physical registers to store data values when performing the data processing operations. Mappings between the architectural registers and the physical registers are stored, and when a data hazard condition is identified with respect to out-of-order program execution of an instruction, an architectural register specified in the instruction is remapped to an available physical register. A reorder buffer stores an entry for each destination architectural register specified by the instruction, entries being stored in program order, and an entry specifies a destination architectural register and an original physical register to which the destination architectural register was mapped before the architectural register remapped to an available physical register.

公开(公告)号：US20160357565A1

公开(公告)日：2016-12-08

申请号：US15133329

申请日：2016-04-20

Applicant: ARM LIMITED

Inventor： Peter Richard GREENHALGH ,  Simon John CRASKE ,  Ian Michael CAULFIELD ,  Max John BATLEY ,  Allan John SKILLMAN ,  Antony John PENTON

IPC: G06F9/38 ,  G06F1/32 ,  G06F9/30

Abstract: Apparatus for processing data 2 is provided with fetch circuitry 16 for fetching program instructions for execution from one or more active threads of instructions having respective program counter values. Pipeline circuitry 22, 24 has a first operating mode and a second operating mode. Mode switching circuitry 30 switches the pipeline circuitry 22, 24, between the first operating mode and the second operating mode in dependence upon a number of active threads of program instructions having program instructions available to be executed. The first operating mode has a lower average energy consumption per instruction executed than the second operating mode and the second operating mode has a higher average rate of instruction execution for a single thread than the first operating mode. The first operating mode may utilise a barrel processing pipeline 22 to perform interleaved multiple thread processing. The second operating mode may utilise an out-of-order processing pipeline 24 for performing out-of-order processing.

Abstract translation: 用于处理数据2的装置具有取出电路16，用于从具有相应程序计数器值的指令的一个或多个有效线程获取用于执行的程序指令。 管道电路22,24具有第一操作模式和第二操作模式。 模式切换电路30根据具有可执行程序指令的程序指令的有效线程数，在第一操作模式和第二操作模式之间切换流水线电路22,24。 第一操作模式具有比第二操作模式执行的每个指令更低的平均能量消耗，并且第二操作模式对于单线程具有比第一操作模式更高的平均指令执行速率。 第一操作模式可以利用桶处理流水线22执行交错多线程处理。 第二操作模式可以利用无序处理流水线24来执行无序处理。

公开(公告)号：US20240004611A1

公开(公告)日：2024-01-04

申请号：US17855856

申请日：2022-07-01

Applicant: Arm Limited

Inventor： Michael Alexander KENNEDY ,  Marco MONTAGNA ,  Karel Hubertus Gerardus WALTERS ,  Ian Michael CAULFIELD

IPC: G06F7/483

CPC classification number: G06F7/483

Abstract: Processing circuitry performs a processing operation to generate a two's complement result value representing a positive or negative number in two's complement representation. Normalization-and-rounding circuitry converts the two's complement result value to a normalized-and-rounded floating-point result value represented using sign-magnitude representation. The normalization-and-rounding circuitry comprises incrementing circuitry to perform an increment addition (e.g. a rounding increment or a conversion increment) to generate a fraction of the normalized-and-rounded floating-point result value. For an operation where the increment addition is required to be performed, tininess detection circuitry detects the after-rounding tininess status based on a still-to-be-incremented version of the normalized-and-rounded floating-point result value prior to the increment addition by the increment circuitry.

公开(公告)号：US20210026635A1

公开(公告)日：2021-01-28

申请号：US16982300

申请日：2019-03-20

Applicant: Arm Limited

Inventor： Frederic Claude Marie PIRY ,  Peter Richard GREENHALGH ,  Ian Michael CAULFIELD ,  Albin Pierrick TONNERRE

IPC: G06F9/30 ,  G06F12/0875 ,  G06F12/0862 ,  G06F21/56 ,  G06F21/54 ,  G06F21/71

Abstract: An apparatus and method are provided for controlling allocation of instructions into an instruction cache storage. The apparatus comprises processing circuitry to execute instructions, fetch circuitry to fetch instructions from memory for execution by the processing circuitry, and an instruction cache storage to store instructions fetched from the memory by the fetch circuitry. Cache control circuitry is responsive to the fetch circuitry fetching a target instruction from a memory address determined as a target address of an instruction flow changing instruction, at least when the memory address is within a specific address range, to prevent allocation of the fetched target instruction into the instruction cache storage unless the fetched target instruction is at least one specific type of instruction. It has been found that such an approach can inhibit the performance of speculation-based caching timing side-channel attacks.

公开(公告)号：US20190163902A1

公开(公告)日：2019-05-30

申请号：US16149297

申请日：2018-10-02

Applicant: Arm Limited

Inventor： Alastair David REID ,  Dominic Phillip MULLIGAN ,  Milosch MERIAC ,  Matthias Lothar BOETTCHER ,  Nathan Yong Seng CHONG ,  Ian Michael CAULFIELD ,  Peter Richard GREENHALGH ,  Frederic Claude Marie PIRY ,  Albin Pierrick TONNERRE ,  Thomas Christopher GROCUTT ,  Yasuo ISHII

IPC: G06F21/55 ,  H04L9/06 ,  G06F12/10 ,  G06F9/38

Abstract: A data processing apparatus comprises branch prediction circuitry adapted to store at least one branch prediction state entry in relation to a stream of instructions, input circuitry to receive at least one input to generate a new branch prediction state entry, wherein the at least one input comprises a plurality of bits; and coding circuitry adapted to perform an encoding operation to encode at least some of the plurality of bits based on a value associated with a current execution environment in which the stream of instructions is being executed. This guards against potential attacks which exploit the ability for branch prediction entries trained by one execution environment to be used by another execution environment as a basis for branch predictions.

公开(公告)号：US20180267805A1

公开(公告)日：2018-09-20

申请号：US15987113

申请日：2018-05-23

Applicant: ARM Limited

Inventor： Ian Michael CAULFIELD ,  Max John BATLEY ,  Chiloda Ashan Senarath PATHIRANE

IPC: G06F9/38

CPC classification number: G06F9/3851

Abstract: A processing pipeline for processing instructions with instructions from multiple threads in flight concurrently may have control circuitry to detect a stalling event associated with a given thread. In response, at least one instruction of the given thread may be flushed from the pipeline, and the control circuitry may trigger fetch circuitry to reduce a fraction of the fetched instructions which are fetched from the given thread. A mechanism is also described to determine when to trigger a predetermined action when a delay in accessing information becomes greater than a delay threshold, and to update the delay threshold based on a difference between a return delay when the information is returned from the storage circuitry and the delay threshold.

公开(公告)号：US20170139708A1

公开(公告)日：2017-05-18

申请号：US14941840

申请日：2015-11-16

Applicant: ARM LIMITED

Inventor： Andrew James Antony LEES ,  Ian Michael CAULFIELD ,  Peter Richard GREENHALGH

IPC: G06F9/30

CPC classification number: G06F9/3851 ,  G06F9/3836

Abstract: Data processing circuitry comprises instruction queue circuitry to maintain one or more instruction queues to store fetched instructions; instruction decode circuitry to decode instructions dispatched from the one or more instruction queues, the instruction decode circuitry being configured to allocate one or more processor resources of a set of processor resources to a decoded instruction for use in execution of that decoded instruction; detection circuitry to detect, for an instruction to be dispatched from a given instruction queue, a prediction indicating whether sufficient processor resources are predicted to be available for allocation to that instruction by the instruction decode circuitry; and dispatch circuitry to dispatch an instruction from the given instruction queue to the instruction decode circuitry, the dispatch circuitry being responsive to the detection circuitry to allow deletion of the dispatched instruction from that instruction queue when the prediction indicates that sufficient processor resources are predicted to be available for allocation to that instruction by the instruction decode circuitry.

公开(公告)号：US20160357554A1

公开(公告)日：2016-12-08

申请号：US14731789

申请日：2015-06-05

Applicant: ARM LIMITED

Inventor： Ian Michael CAULFIELD ,  Peter Richard GREENHALGH ,  Simon John CRASKE ,  Max John BATLEY ,  Allan John SKILLMAN ,  Antony John PENTON

IPC: G06F9/30

CPC classification number: G06F9/3836 ,  G06F9/3855 ,  G06F9/3873 ,  G06F9/3889

Abstract: An apparatus comprises a processing pipeline comprising out-of-order execution circuitry and second execution circuitry. Control circuitry monitors at least one reordering metric indicative of an extent to which instructions are executed out of order by the out-of-order execution circuitry, and controls whether instructions are executed using the out-of-order execution circuitry or the second execution circuitry based on the reordering metric. A speculation metric indicative of a fraction of executed instructions that are flushed due to a mis-speculation can also be used to determine whether to execute instructions on first or second execution circuitry having different performance or energy consumption characteristics.

Abstract translation: 一种装置包括一个包括无序执行电路和第二执行电路的处理流水线。 控制电路监视至少一个重新排序度量，其指示由无序执行电路执行的指令不顺序的程度，并且控制是否使用无序执行电路或第二执行电路来执行指令 基于重新排序指标。 指示由于错误推测而被刷新的执行指令的一部分的猜测度量也可以用于确定是否执行具有不同性能或能量消耗特性的第一或第二执行电路上的指令。