计算机专业英语 学习笔记 2

What is a processor

A processor is a functional unit thatinterprets and carries out instructions. Every processor comes with a uniqueset of operations such as ADD, STORE, or LOAD that represent the processor’sinstruction set. Computer designers are fond of calling their computersmachines, so the instruction set is sometimes referred to as machineinstructions and the binary language in which they are written is calledmachine language. You shouldn’t confuse the processor’s instruction set withthe instructions found in high-level programming languages, such as BASIC orPascal.

An instruction is made up of operationsthat specify the function to be performed and operands that operands thatrepresent the data to be operated on. For example, if an instruction is toperform the operation of adding two numbers, it must know what the two numbersare and where the two numbers are. When the numbers are stored in the computer’smemory, they have their addresses to indicate where they are. So if an operandrefers to data in the computer memory it is called an address. The processor’sjob is to retrieve(检索) instructions and operands from memory and to perform eachoperation. Having done that, it signals memory to send it the next instruction.

This step-by-step operation is repeatedover and over again at awesome speed. A timer called a clock releases preciselytimed electrical signals that provide a regular pulse for the processor’s work.The term that is used to measure the computer’s speed is borrowed from thedomain of electrical engineering and is called a megahertz which means millioncycles per second. For example, in an 8-MHz processor, the computer’s clockticks 8 million times to every 1 second tick of an ordinary clock.

A processor is composed of two functionalunits – a control unit and an arithmetic/logic unit – and a set of specialworkspaces called registers.

The control unit>

The control unit is the functional unitthat is responsible for supervising the operation of the entire computersystem. In some ways, it is analogous to a telephone switch-board(交换机) with intelligence because itmakes the connections between various functional units of the computer systemand calls into(调用) operationeach unit that is required by the program currently in operation.

The control unit fetches instructions frommemory and determines their types or decodes them. It then breaks eachinstruction into a serious of simple small steps or actions. By doing this, itcontrols the step-by-step operation of the entire computer system.

The arithmetic and logic unit>

The arithmetic and logic unit is thefunctional unit that provides the computer with logical and computationalcapabilities. Data are brought into the ALU by the control unit, and the ALUperforms whatever arithmetic or logic operations are required to help carry outthe instruction.

Arithmetic operations include adding,subtracting, multiplying, and dividing. Logic operations make a comparison andtake action based on the results. For example, two numbers might be compared todetermine if they are equal. If they are equal, processing will continue; ifthey are not equal, processing will stop.

Registers>

A register is a storage location inside theprocessor. Registers in the control unit are used to keep track of the overallstatus(状态) of theprogram that is running. Control unit registers store information such as thecurrent instruction, the location of the next instruction to be executed, andthe operands of the instruction. In the ALU, registers store data items thatare added, subtracted, multiplied, divided, and compared. Other registers storethe results of arithmetic and logic operations.

An important factor that affects the speedand performance of a processor is the size of the registers. Technically, theterm word size (also called word length) describes the size of an operandregister, but it is also used more loosely(自由的) to describe the size of the pathways to and from the processor. Currently,word sizes in general purpose computers range from 8 to 64 bits. If the operandregisters of a processor are 16 bits wide, the processor is said to be a 16-bitprocessor.

Instruction 指令 clock 时钟 instruction set 指令集 megahertz 兆赫 processor 处理器

Control unit 控制器 operation 操作，操作码 arithmetic and logic unit 算术/逻辑部件

Operand 操作数 word size ( word length) 字长 register 寄存器 machine language 机器语言

Match the following terms to theappropriate definition.

A functional unit that interprets andcarries out instructions(processor).

Million cycles per second(megahertz).

A unique set of operations that comes withevery processor.(instruction set)

The function unit that is responsible forsupervising the operation of the entire computer system.(control unit)

A timer in a processor that releasesprecisely timed signals that provide a pulse for the processor’s work.(clock)

A function unit that provides the computerwith logical and computational capability.(arithmetic and logic unit)ALU

The binary language in which a computer’sinstruction set is written.(machine language)

A storage location inside theprocessor.(register)

The part of an instruction that specifiesthe function that is to be performed.(operation)

The term used to describe the size ofoperand registers and buses.(word size)

The part of an instruction that tells wheredata that are operated on are located.(operand)

Fill in the blanks with appropriate wordsor phrases.

We usually call our computers machines.

An instruction set can sometimes bereferred to as machine instructions.

The binary language is called machinelanguage.

We don’t confuse the processor’sinstruction set with the instructions of high-level programming languages.

An instruction consists of operations andoperands.

An operand that refers to data in thememory is called an address.

A timer can give precisely timed electricalsignals.

A processor includes two functional units,they are control unit and ALU.

The ways by which the control unit worksare analogous to a telephone switch-board with intelligence.

The control unit takes out the instructionsfrom memory.