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Slot (computer Architecture)
A slot comprises the operation issue and data path machinery surrounding a set of one or more execution unit (also called a functional unit (FU)) which share these resources. The term slot is common for this purpose in very long instruction word (VLIW) computers, where the relationship between operation in an instruction and pipeline to execute it is explicit. In dynamically scheduled machines, the concept is more commonly called an ''execute pipeline''. Modern conventional central processing units (CPU) have several compute pipelines, for example: two arithmetic logic units (ALU), one floating point unit (FPU), one Streaming SIMD Extensions (SSE) (such as MMX), one branch. Each of them can issue one instruction per basic instruction cycle, but can have several instructions in process. These are what correspond to slots. The pipelines may have several FUs, such as an adder and a multiplier Multiplier may refer to: Mathematics * Multiplier (arithmetic), the number of multiples ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Execution Unit
In computer engineering, an execution unit (E-unit or EU) is a part of a processing unit that performs the operations and calculations forwarded from the instruction unit. It may have its own internal control sequence unit (not to be confused with a CPU's main control unit), some registers, and other internal units such as an arithmetic logic unit, address generation unit, floating-point unit, load–store unit, branch execution unit or other smaller and more specific components, and can be tailored to support a certain datatype, such as integers An integer is the number zero (0), a positive natural number (1, 2, 3, ...), or the negation of a positive natural number (−1, −2, −3, ...). The negations or additive inverses of the positive natural numbers are referred to as negative in ... or floating-points. It is common for modern processing units to have multiple parallel functional units within its execution units, which is referred to as superscalar design. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very Long Instruction Word
Very long instruction word (VLIW) refers to instruction set architectures that are designed to exploit instruction-level parallelism (ILP). A VLIW processor allows programs to explicitly specify instructions to execute in parallel, whereas conventional central processing units (CPUs) mostly allow programs to specify instructions to execute in sequence only. VLIW is intended to allow higher performance without the complexity inherent in some other designs. The traditional means to improve performance in processors include dividing instructions into sub steps so the instructions can be executed partly at the same time (termed ''pipelining''), dispatching individual instructions to be executed independently, in different parts of the processor (''superscalar architectures''), and even executing instructions in an order different from the program (''out-of-order execution''). These methods all complicate hardware (larger circuits, higher cost and energy use) because the processor mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instruction (computer Science)
In computer science, an instruction set architecture (ISA) is an abstract model that generally defines how software controls the CPU in a computer or a family of computers. A device or program that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ''implementation'' of that ISA. In general, an ISA defines the supported Machine code, instructions, data types, Register (computer), registers, the hardware support for managing Computer memory, main memory, fundamental features (such as the memory consistency, addressing modes, virtual memory), and the input/output model of implementations of the ISA. An ISA specifies the behavior of machine code running on implementations of that ISA in a fashion that does not depend on the characteristics of that implementation, providing binary compatibility between implementations. This enables multiple implementations of an ISA that differ in characteristics such as Computer performance, performa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipeline (computing)
In computing, a pipeline, also known as a data pipeline, is a set of data processing elements connected in series, where the output of one element is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion. Some amount of buffer storage is often inserted between elements. Concept and motivation Pipelining is a commonly used concept in everyday life. For example, in the assembly line of a car factory, each specific task—such as installing the engine, installing the hood, and installing the wheels—is often done by a separate work station. The stations carry out their tasks in parallel, each on a different car. Once a car has had one task performed, it moves to the next station. Variations in the time needed to complete the tasks can be accommodated by "buffering" (holding one or more cars in a space between the stations) and/or by "stalling" (temporarily halting the upstream stations), until the next station becomes avai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Processing Unit
A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs). The form, CPU design, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic operation, arithmetic and Bitwise operation, logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the #Fetch, fetching (from memory), #Decode, decoding and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (opcode); 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 (electroni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floating Point Unit
A floating-point unit (FPU), numeric processing unit (NPU), colloquially math coprocessor, is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Modern designs generally include a fused multiply-add instruction, which was found to be very common in real-world code. Some FPUs can also perform various transcendental functions such as exponential or trigonometric calculations, but the accuracy can be low, so some systems prefer to compute these functions in software. Floating-point operations were originally handled in software in early computers. Over time, manufacturers began to provide standardized floating-point libraries as part of their software collections. Some machines, those dedicated to scientific processing, would include specialized hardware to perform some of these tasks with much greater speed. The introduction of microcode in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streaming SIMD Extensions
In computing, Streaming SIMD Extensions (SSE) is a single instruction, multiple data ( SIMD) instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in its Pentium III series of central processing units (CPUs) shortly after the appearance of Advanced Micro Devices (AMD's) 3DNow!. SSE contains 70 new instructions (65 unique mnemonics using 70 encodings), most of which work on single precision floating-point data. SIMD instructions can greatly increase performance when exactly the same operations are to be performed on multiple data objects. Typical applications are digital signal processing and graphics processing. Intel's first IA-32 SIMD effort was the MMX instruction set. MMX had two main problems: it re-used existing x87 floating-point registers making the CPUs unable to work on both floating-point and SIMD data at the same time, and it only worked on integers. SSE floating-point instructions operate on a new independent register s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMX (instruction Set)
MMX is a ''single instruction, multiple data'' (SIMD) instruction set architecture designed by Intel, introduced on January 8, 1997 with its Pentium P5 (microarchitecture) based line of microprocessors, named "Pentium with MMX Technology". It developed out of a similar unit introduced on the Intel i860, and earlier the Intel i750 video pixel processor. MMX is a processor supplementary capability that is supported on IA-32 processors by Intel and other vendors . AMD also added MMX instruction set in its AMD K6, K6 processor. ''The New York Times'' described the initial push, including Super Bowl advertisements, as focused on "a new generation of glitzy multimedia products, including videophones and 3-D video games." MMX has subsequently been extended by several programs by Intel and others: 3DNow!, Streaming SIMD Extensions (SSE), and ongoing revisions of Advanced Vector Extensions (AVX). Overview Naming MMX is officially a meaningless initialism trademarked by Intel; unoffici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branch (computer Science)
A branch, jump or transfer is an instruction in a computer program that can cause a computer to begin executing a different instruction sequence and thus deviate from its default behavior of executing instructions in order. ''Branch'' (or ''branching'', ''branched'') may also refer to the act of switching execution to a different instruction sequence as a result of executing a branch instruction. Branch instructions are used to implement control flow in program loops and conditionals (i.e., executing a particular sequence of instructions only if certain conditions are satisfied). A branch instruction can be either an ''unconditional branch'', which always results in branching, or a ''conditional branch'', which may or may not cause branching depending on some condition. Also, depending on how it specifies the address of the new instruction sequence (the "target" address), a branch instruction is generally classified as ''direct'', ''indirect'' or ''relative'', meaning that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instruction Cycle
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 Program counter The program counter (PC) is a register that holds the memory address of the next instruction to be executed. After each instruction copy to the memory address register (MAR), the PC can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adder (electronics)
An adder, or summer, is a digital circuit that performs addition of numbers. In many computers and other kinds of microprocessor, processors, adders are used in the arithmetic logic units (ALUs). They are also used in other parts of the processor, where they are used to calculate address space, addresses, database index, table indices, increment and decrement operators and similar operations. Although adders can be constructed for many number representations, such as binary-coded decimal or excess-3, the most common adders operate on binary numbers. In cases where two's complement or ones' complement is being used to represent negative numbers, it is trivial to modify an adder into an adder–subtractor. Other signed number representations require more logic around the basic adder. History George Stibitz invented the 2-bit binary adder (the Model K (calculator), Model K) in 1937. Binary adders Half adder The half adder adds two single binary digits A and B. It has two outputs, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
