Digital-electronics 简明教程

Arithmetic Logic Unit in Digital Electronics

Arithmetic Logic Unit (ALU) 是计算系统中的基本组件，如计算机。它基本上是在计算系统中的中央处理器 (CPU) 内的实际数据处理组件。它执行所有算术和逻辑运算，并构成现代计算机技术的支柱。

The Arithmetic Logic Unit (ALU) is the fundamental component in a computing system like a computer. It is basically the actual data processing element within the central processing unit (CPU) in a computing system. It performs all the arithmetic and logical operations and forms the backbone of modern computer technology.

在本章中，我们将说明算术逻辑单元的工作原理，连同其主要组件、其功能和 ALU 在数字系统设计领域的重要性。

In this chapter, we will explain the working of the arithmetic logic unit, along with its main components, their functions, and the importance of the ALU in the field of digital system designs.

What is Arithmetic Logic Unit?

缩写为 ALU 的算术逻辑单元被认为是每个中央处理器 (CPU) 的引擎或核心。ALU 基本上是一个组合逻辑电路，可以在数字数据（二进制格式的数据）上执行算术和逻辑运算。它还可以执行给定计算系统的指令，例如数字计算机。

Arithmetic Logic Unit abbreviated as ALU is considered as the engine or heart of every central processing unit (CPU). ALU is basically a combination logic circuit that can perform arithmetic and logical operation on digital data (data in binary format). It can also execute instructions given to a computing system like a digital computer.

arithmetic logic unit

在数字计算系统的复杂架构中，算术逻辑单元或 ALU 扮演着重要角色，因为它执行和处理所有指令、执行计算、处理二进制数据并执行各种决策操作。

Within the complex architecture of a digital computing system, the arithmetic logic unit or ALU plays an important role as it executes and processes all the instructions, performs calculations, manipulates binary data, and performs various decision-making operations.

算术逻辑单元的开发始于对高效、高速和准确的数据处理和计算的需求。随着电子技术的发展，ALU 已成为一种高度复杂化的数字数据处理设备，可以处理大量的复杂指令和计算任务。

The development of arithmetic logic unit begins with the need for efficient, high speed, and accurate data processing and computation. With the advancement in electronics technologies, ALU has become a highly sophisticated digital data processing device that can handle a large number of complex instructions and computational tasks.

当今的 ALU 在计算操作中提供高准确度、高精度和明显快速的处理速度。

Today’s ALU provides high accuracy, precision, and significantly fast processing speed in computing operations.

Features of Arithmetic Logic Unit

以下是算术逻辑单元的一些主要特征 −

Here are some key features of arithmetic logic unit −

  1. The ALU can perform all arithmetic and logic operations such as addition, subtraction, multiplication, division, logical comparisons, etc.

  2. It can also perform bitwise and mathematical operations on binary numbers.

  3. It contains two segments namely, AU (arithmetic unit) and LU (logic unit) to perform arithmetic operations and logical operations respectively.

  4. It is the computational powerhouse within a central processing unit (CPU).

  5. ALU is the part of every CPU where actual data processing takes place.

  6. ALU is responsible for interpreting the code instructions based on which operations to be performed on the input data.

  7. Once the data processing is completed, the ALU sends the outcomes to the memory unit or output unit.

Main Components of Arithmetic Logic Unit

算术逻辑单元由各种功能部分组成，负责执行特定操作，例如加法、减法、乘法、除法、比较等。下面说明了算术逻辑单元的一些关键组件：

The arithmetic logic unit consists of various functional parts that are responsible for performing specific operations like addition, subtraction, multiplication, division, comparison, and more. Some of the key components of the arithmetic logic unit are explained below −

Arithmetic Unit

算术逻辑单元的算术单元 (AU) 段中使用的主要组件如下：

The main components used in the arithmetic unit (AU) segment of the arithmetic logic unit are as follows −

加法器或二进制加法器是算术逻辑单元的重要组成部分之一。它执行两个或多个二进制数的加法。为了完成此操作，它执行一系列逻辑和算术运算。算术逻辑单元中使用的一些常见加法器类型有半加法器、全加法器、并行加法器和波纹进位加法器。每种类型的加法器都经过设计和优化以执行特定的计算操作。

The adder or binary adder is one of the important components of the arithmetic logic unit. It performs the addition of two or more binary numbers. To accomplish this operation, it performs a series of logical and arithmetic operations. Some common types of adders used in the arithmetic ogic unit are half-adder, full-adder, parallel adder, and ripple carry adder. Each type of adder is designed and optimized to perform a specific computing operation.

减法器是另一个数字组合电路，设计用于执行二进制数的减法。在大多数算术逻辑单元中，减法器使用 2 的补码算术对二进制数执行减法。

The subtractor is another digital combinational circuit designed to perform subtraction of binary numbers. In most arithmetic logic unit, the subtractor uses 2’s complement arithmetic to perform subtraction on binary numbers.

在更复杂和高级的算术逻辑单元中，还实现了专门的乘法器和除法器电路，以对二进制数执行乘法和除法。这些电路使用高级处理技术（如迭代或并行处理）来完成这些操作。

In more complex and advanced arithmetic logic units, dedicated multiplier and divider circuits are also implemented to perform multiplication and division on binary numbers. These circuits use advanced processing techniques like iterative or parallel processing to accomplish these operations.

Logic Unit

ALU 的逻辑单元 (LU) 由负责执行布尔或比较运算的组件组成。以下是 ALU 逻辑单元的一些主要组件：

The logic unit (LU) of the ALU comprises the components responsible for performing Boolean or comparison operations. The following are some main components of the logic unit of an ALU −

与门、或门、非门、与非门、或非门、异或门和异或非门等逻辑门是逻辑单元的关键组件。这些是标准逻辑电路，可以根据某些预定义的逻辑指令处理输入数据并生成所需的输出。

The logic gates like AND, OR, NOT, NAND, NOR, XOR, and XNOR are the key components of logic unit. These are standard logic circuits that can manipulate input data based on some predefined logical instructions and generate a desired output.

每个逻辑门都可以执行特定的逻辑运算。然而，不同类型的逻辑门可以以特定方式连接在一起，以执行复杂的逻辑运算。

Each logic gate can perform a specific logical operation. However, different types of logic gates can be connected together in a specific manner to perform complex logical operations.

此处说明了每种类型逻辑门的简要概述：

The brief overview of each type of logic gate is explained here −

  1. AND Gate − It performs the Boolean multiplication on input binary data. Its output is logic 1 or true, only when all its inputs are logic 1 or true.

  2. OR Gate − The OR gate performs the Boolean addition of input binary data. It generates a logic 1 or true output, if any of its inputs is logic 1 or true.

  3. NOR Gate − The NOT gate performs the inversion operation. It gives a logic 1 or true output when its input is logic 0 or false and vice-versa.

  4. NAND Gate − The NAND gate performs the NOTed AND operation and produces a logic 1 or true output when both inputs or any of the inputs is logic 0 or false.

  5. NOR Gate − The NOR gate performs the NOTed OR operation and generates a logic 1 or true output when all its inputs are logic 0 or false.

  6. XOR Gate − The XOR gate performs the exclusive OR operation and produces a logic 1 or true output when its both inputs are dissimilar. Hence, it is used as inequality detector.

  7. XNOR Gate − The XNOR gate performs the exclusive NOR operation and gives a logic 1 or true output when both its inputs are similar. Thus, it is used as an equality detector.

以上介绍了算术逻辑单元的结构和组件。下面了解 ALU 可执行哪些功能。

This is all about structure and components of the arithmetic logic unit. Let us now understand what functions an ALU can perform.

Functions of Arithmetic Logic Unit

算术逻辑单元可在数字计算系统中执行广泛的功能和运算。下面说明了算术逻辑单元执行的一些重要功能：

The arithmetic logic unit can perform a wide range of functions and operations in digital computing systems. Some important functions that an arithmetic logic unit perform are explained below −

Arithmetic Operations

算术运算是在算术逻辑单元中执行的主要功能之一。这类别运算包括二进制数的加法、减法、乘法和除法。所有这些运算构成了算术逻辑单元可执行的数学计算的基础。

The arithmetic operations are one of the primary functions that the arithmetic logic unit performs. This category of operations includes addition, subtraction, multiplication, and division of binary numbers. All these operations form the basis of mathematical computations that the arithmetic logic unit can perform.

Logical Operations

算术逻辑单元还可以执行各种逻辑运算，如 AND 运算、OR 运算、NOT 运算等。这些逻辑运算构成了决策和数据处理过程的基础。

The arithmetic logic unit can also perform various logical operations such as AND operation, OR operation, NOT operation, etc. These logical operations form the basis of decision making and data manipulation processes.

Comparison Operations

算术逻辑单元还有助于执行各种比较运算，如等于、不等于、小于、大于等。这些比较运算对于决策过程至关重要。

The arithmetic logic unit also facilitates to perform various comparison operations such as equal to, not equal to, less than, greater than, etc. These comparison operations are essential in decision making processes.

Shift Operations

算术逻辑单元还可以对二进制数执行移位运算，如左移和右移。这些运算对于乘法和除法运算很重要。移位运算可以在位级别操纵二进制数据，从而优化算术计算。

The arithmetic logic unit can also perform shift operations on binary numbers such as left shift and right shift. These operations are important in multiplication and division operations. The shift operations can manipulate binary data at bit level and hence optimize the arithmetic calculations.

Working of Arithmetic Logic Unit

算术逻辑单元的工作取决于输入数据和控制信号的组合。换言之，算术逻辑单元接收输入数据和控制信号，然后解释这些数据和信号以执行特定运算。

The working of the arithmetic logic unit depends on a combination of input data and control signals. In other words, the arithmetic logic unit receives the input data and control signals and then interpret these data and signals to perform specific operations.

让我们通过将其分解为子组件，详细了解算术逻辑单元的工作原理。

Let us understand the working of the arithmetic logic unit in detail by breaking it down in sub-components.

Receiving Input Data and Control Signals

算术逻辑单元从用户接收输入数据和指定要执行的运算的一组控制信号。通过输入数据路径接收数据，而从控制单元接收控制信号。

The arithmetic logic unit receives the input data from the user and a set of control signals that specifies the operation to be performed. The data is received through the input data path while the control signals are received from the control unit.

Execution of Operation

一旦算术逻辑单元接收到输入数据和控制信号，它就会在算术单元、逻辑单元、比较单元或移位单元中选择一个合适的函数组件来执行特定运算。一旦运算完成，ALU 会将结果发送到存储器单元进行存储或发送到输出单元。

Once the arithmetic logic unit received the input data and control signals, it selects an appropriate functional component among arithmetic unit, logic unit, comparison unit, or shift unit to perform the specific operation. Once the operation completes, the ALU sends the results to the memory unit for storage or output unit.

Significance of Arithmetic Logic Unit

在数字电子和计算技术领域，算术逻辑单元由于以下原因而发挥着重要作用：

In the field of digital electronics and computing technology, the arithmetic logic unit plays an important role because of the following reasons −

  1. It can perform the arithmetic, logical, and comparison operations with very high accuracy, precision, and efficiency.

  2. It can also perform complex data processing and decision-making operations.

  3. ALU can execute complex processing tasks at a very high speed that results in better performance and higher efficiency.

  4. ALU introduces versatility as it can execute a wide range of computational tasks.

Conclusion

以上是关于算术逻辑单元 (ALU) 的所有内容，它是数字电子和现代计算系统中的一个重要组合逻辑电路。它作为中央处理单元 (CPU) 的核心，执行各种运算，包括算术、逻辑和比较运算。在数字计算系统中，算术逻辑单元充当根据指令处理输入数据的主要功能单元。在本节中，我们研究了与算术逻辑单元相关的所有重要概念。

This is all about arithmetic logic unit (ALU) which is an important combinational logic circuit in digital electronics and modern computing systems. It acts as the heart of central processing unit (CPU) and executes all kinds of operations including arithmetic, logical, and comparison operations. In a digital computing system, the arithmetic logic unit acts as a primary functional unit that processes the input data based on the instructions. In this chapter, we have studied all the important concepts related to the arithmetic logic unit.