计算机英语(第三版) 1-1.3作者：刘兆毓、郑家农(普通高等教育“十一五”国家级规划教材).pptVIP

* PART 1 COMPUTER HARDWARE CHAPTER 1 PRINCIPLES OF COMPUTER ORGANIZATION 1.3 WHAT IS A PROCESSOR chapter 1-1.3 1.3 WHAT IS A PROCESSOR Main point: Main point: ● Instruction and Instruction set ● Three units of CPU ● Operation of CPU A processor is A processor is a functional unit that interprets and carries out instructions. Every processor comes with a unique set of operations such as ADD, STORE, or LOAD that represent the processor’s instruction set. Computer designers are fond of calling their computers machines［1］, so the instruction set is sometimes referred to as machine instructions and the binary language in which they are written is called machine language! You shouldn’t confuse the processor’s instruction set with the instructions found in high-level programming languages, such as BASIC or Pascal. 定语从句 结果状语从句 定语从句 An instruction is made up of operations that specify the function to be performed and operands that represent the data to be operated on. For example, if an instruction is to perform the operation of adding two numbers, it must know (1) what the two numbers are and (2) where the two numbers are. When the numbers are stored in the computer’s memory, they have their addresses to indicate where they are. So if an operand refers to data in the computer’s memory it is called an address. An instruction 定语从句 定语从句 时间状语从句 条件状语从句 The processor’s job is to retrieve instructions and operands from memory and to perform each operation. Having done that , it signals memory to send it the next instruction. This step-by-step operation is repeated over and over again at awesome speed. A timer called a clock releases precisely timed 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 the domain of electrical engineering and is called a megahertz (MHz), which means million cycles per second. For example, in a