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ARM Cortex-A77
The ARM Cortex-A77 is a central processing unit implementing the ARMv8.2-A 64-bit instruction set designed by ARM Holdings' Austin design centre. ARM announced an increase of 23% and 35% in integer and floating point performance, respectively. Memory bandwidth increased 15% relative to the A76. Design The Cortex-A77 serves as the successor of the Cortex-A76. The Cortex-A77 is a 4-wide decode out-of-order superscalar design with a new 1.5K macro-OP (MOPs) cache. It can fetch 4 instructions and 6 Mops per cycle. And rename and dispatch 6 Mops, and 13 µops per cycle. The out-of-order window size has been increased to 160 entries. The backend is 12 execution ports with a 50% increase over Cortex-A76. It has a pipeline depth of 13 stages and the execution latencies of 10 stages. There are six pipelines in the integer cluster – an increase of two additional integer pipelines from Cortex-A76. One of the changes from Cortex-A76 is the unification of the issue queues. Previously ...
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ARM Holdings
Arm is a British semiconductor and software design company based in Cambridge, England. Its primary business is in the design of ARM processors (CPUs). It also designs other chips, provides software development tools under the DS-5, RealView and Keil brands, and provides systems and platforms, system-on-a-chip (SoC) infrastructure and software. As a "holding" company, it also holds shares of other companies. Since 2016, it has been owned by Japanese conglomerate SoftBank Group. While ARM CPUs first appeared in the Acorn Archimedes, a desktop computer, today's systems include mostly embedded systems, including ARM CPUs used in virtually all smartphones. Systems such as iPhones and Android smartphones frequently include many chips, from many different providers, that include one or more licensed Arm cores, in addition to those in the main Arm-based processor. Arm's core designs are also used in chips that support all the most common network-related technologies. Processors ba ...
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ARM DynamIQ
ARM big.LITTLE is a heterogeneous computing architecture developed by ARM Holdings, coupling relatively battery-saving and slower processor cores (''LITTLE'') with relatively more powerful and power-hungry ones (''big''). Typically, only one "side" or the other will be active at once, but all cores have access to the same memory regions, so workloads can be swapped between Big and Little cores on the fly. The intention is to create a multi-core processor that can adjust better to dynamic computing needs and use less power than clock scaling alone. ARM's marketing material promises up to a 75% savings in power usage for some activities. Most commonly, ARM big.LITTLE architectures are used to create a multi-processor system-on-chip (MPSoC). In October 2011, big.LITTLE was announced along with the Cortex-A7, which was designed to be architecturally compatible with the Cortex-A15. In October 2012 ARM announced the Cortex-A53 and Cortex-A57 (ARMv8-A) cores, which are also intercom ...
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Semiconductor Intellectual Property Core
In electronic design, a semiconductor intellectual property core (SIP core), IP core, or IP block is a reusable unit of logic, cell, or integrated circuit layout design that is the intellectual property of one party. IP cores can be licensed to another party or owned and used by a single party. The term comes from the licensing of the patent or source code copyright that exists in the design. Designers of application-specific integrated circuits (ASIC) and systems of field-programmable gate array (FPGA) logic can use IP cores as building blocks. History The licensing and use of IP cores in chip design came into common practice in the 1990s. There were many licensors and also many foundries competing on the market. In 2013, the most widely licensed IP cores are from Arm Holdings (43.2% market share), Synopsys Inc. (13.9% market share), Imagination Technologies (9% market share) and Cadence Design Systems (5.1% market share). Types of IP cores The use of an IP core in chip ...
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Advanced Encryption Standard
The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a variant of the Rijndael block cipher developed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen, who submitted a proposal to NIST during the AES selection process. Rijndael is a family of ciphers with different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits. AES has been adopted by the U.S. government. It supersedes the Data Encryption Standard (DES), which was published in 1977. The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data. In the United States, AES was announced by the NIST as U.S. FIPS PUB 197 (FIPS 197) on Novemb ...
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Arithmetic Logic Unit
In computing, an arithmetic logic unit (ALU) is a Combinational logic, combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. It is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). The inputs to an ALU are the data to be operated on, called operands, and a code indicating the operation to be performed; the ALU's output is the result of the performed operation. In many designs, the ALU also has status inputs or outputs, or both, which convey information about a previous operation or the current operation, respectively, between the ALU and external status registers. Signals An ALU has a variety of input and output net (electronics), nets, which are the electrical conductors used to convey Digital signal (electronics), digi ...
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Execution Unit
In computer engineering, an execution unit (E-unit or EU) is a part of the central processing unit (CPU) that performs the operations and calculations as instructed by the computer program. It may have its own internal control sequence unit (not to be confused with the CPU's main control unit), some registers, and other internal units such as an arithmetic logic unit (ALU), address generation unit (AGU), floating-point unit (FPU), load-store unit (LSU), branch execution unit (BEU) or some smaller and more specific components."Execution Unit" discussion from the University of Massachusetts Amherst
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Re-order Buffer
A re-order buffer (ROB) is a hardware unit used in an extension to the Tomasulo algorithm to support out-of-order and speculative instruction execution. The extension forces instructions to be committed in-order. The buffer is a circular buffer (to provide a FIFO instruction ordering queue) implemented as an array/vector (which allows recording of results against instructions as they complete out of order). There are three stages to the Tomasulo algorithm: "Issue", "Execute", "Write Result". In an extension to the algorithm, there is an additional "Commit" stage. During the Commit stage, instruction results are stored in a register or memory. The "Write Result" stage is modified to place results in the re-order buffer. Each instruction is tagged in the reservation station with its index in the ROB for this purpose. The contents of the buffer are used for data dependencies of other instructions scheduled in the buffer. The head of the buffer will be committed once its result is ...
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Execution Engine
Capital punishment, also known as the death penalty, is the state-sanctioned practice of deliberately killing a person as a punishment for an actual or supposed crime, usually following an authorized, rule-governed process to conclude that the person is responsible for violating norms that warrant said punishment. The sentence ordering that an offender is to be punished in such a manner is known as a death sentence, and the act of carrying out the sentence is known as an execution. A prisoner who has been sentenced to death and awaits execution is ''condemned'' and is commonly referred to as being "on death row". Crimes that are punishable by death are known as ''capital crimes'', ''capital offences'', or ''capital felonies'', and vary depending on the jurisdiction, but commonly include serious crimes against the person, such as murder, mass murder, aggravated cases of rape (often including child sexual abuse), terrorism, aircraft hijacking, war crimes, crimes against huma ...
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Instruction Fetch
The instruction cycle (also known as the fetch–decode–execute cycle, or simply the fetch-execute cycle) is the cycle that the central processing unit (CPU) follows from boot-up until the computer has shut down in order to process instructions. It is composed of three main stages: the fetch stage, the decode stage, and the execute stage. In simpler CPUs, the instruction cycle is executed sequentially, each instruction being processed before the next one is started. In most modern CPUs, the instruction cycles are instead executed concurrently, and often in parallel, through an instruction pipeline: the next instruction starts being processed before the previous instruction has finished, which is possible because the cycle is broken up into separate steps. Role of components The program counter (PC) is a special register that holds the memory address of the next instruction to be executed. During the fetch stage, the address stored in the PC is copied into the memory addres ...
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Micro-operation
In computer central processing units, micro-operations (also known as micro-ops or μops, historically also as micro-actions) are detailed low-level instructions used in some designs to implement complex machine instructions (sometimes termed macro-instructions in this context). Usually, micro-operations perform basic operations on data stored in one or more registers, including transferring data between registers or between registers and external buses of the central processing unit (CPU), and performing arithmetic or logical operations on registers. In a typical fetch-decode-execute cycle, each step of a macro-instruction is decomposed during its execution so the CPU determines and steps through a series of micro-operations. The execution of micro-operations is performed under control of the CPU's control unit, which decides on their execution while performing various optimizations such as reordering, fusion and caching. Optimizations Various forms of μops have long bee ...
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Prefetcher
The Prefetcher is a component of Microsoft Windows which was introduced in Windows XP. It is a component of the Memory Manager that can speed up the Windows boot process and shorten the amount of time it takes to start up programs. It accomplishes this by caching files that are needed by an application to RAM as the application is launched, thus consolidating disk reads and reducing disk seeks. This feature was covered by US patent 6,633,968. Since Windows Vista, the Prefetcher has been extended by SuperFetch and ReadyBoost. SuperFetch attempts to accelerate application launch times by monitoring and adapting to application usage patterns over periods of time, and caching the majority of the files and data needed by them into memory in advance so that they can be accessed very quickly when needed. ReadyBoost (when enabled) uses external memory like a USB flash drive to extend the system cache beyond the amount of RAM installed in the computer. ReadyBoost also has a component calle ...
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Runahead
{{No footnotes, date=November 2010 Runahead is a technique that allows a microprocessor to pre-process instructions during cache miss cycles instead of stalling. The pre-processed instructions are used to generate instruction and data stream prefetches by detecting cache misses before they would otherwise occur by using the idle execution resources to calculate instruction and data stream fetch addresses using the available information that is independent of the cache miss. The principal hardware cost is a means of checkpointing the register file state and preventing pre-processed stores from modifying memory. This checkpointing can be accomplished using very little hardware since all results computed during runahead are discarded after the cache miss has been serviced, at which time normal execution resumes using the checkpointed register file state. Branch outcomes computed during runahead mode can be saved into a shift register, which can be used as a highly accurate branch pre ...
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