Execution unit
Encyclopedia
In computer engineering
, an execution unit (also called a functional unit) is a part of a CPU
that performs the operations and calculations called for by the Branch Unit, which receives data from the CPU. It may have its own internal control sequence unit (not to be confused with the CPUs main control unit
), some register
s, and other internal units such as a sub-ALU
or FPU
, or some smaller, more specific components.
It is commonplace for modern CPUs to have multiple parallel execution units, referred to as scalar or superscalar
design. The simplest arrangement is to use one, the bus manager, to manage the memory interface, and the others to perform calculations. Additionally, modern CPUs' execution units are usually pipelined.
Computer engineering
Computer engineering, also called computer systems engineering, is a discipline that integrates several fields of electrical engineering and computer science required to develop computer systems. Computer engineers usually have training in electronic engineering, software design, and...
, an execution unit (also called a functional unit) is a part of a CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
that performs the operations and calculations called for by the Branch Unit, which receives data from the CPU. It may have its own internal control sequence unit (not to be confused with the CPUs main control unit
Control unit
A control unit in general is a central part of the machinery that controls its operation, provided that a piece of machinery is complex and organized enough to contain any such unit. One domain in which the term is specifically used is the area of computer design...
), some register
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
s, and other internal units such as a sub-ALU
Arithmetic logic unit
In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...
or FPU
Floating point unit
A floating-point unit 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...
, or some smaller, more specific components.
It is commonplace for modern CPUs to have multiple parallel execution units, referred to as scalar or superscalar
Superscalar
A superscalar CPU architecture implements a form of parallelism called instruction level parallelism within a single processor. It therefore allows faster CPU throughput than would otherwise be possible at a given clock rate...
design. The simplest arrangement is to use one, the bus manager, to manage the memory interface, and the others to perform calculations. Additionally, modern CPUs' execution units are usually pipelined.