计算机导论复习.ppt
计算机导论考前辅导学习方法应试方法 认真对待作业题，作业题就是考试题 老师上课讲的内容就是考试内容（不必死扣书本） 考试不交白卷，越不会越多写（相关公式、概念、自己的想法） 大学考试考的是记忆力，请珍惜自己的大脑 神通广大的打印店（复习资料、历年试卷）Chapter 1 IntroductionComputer Is a programmable data processor that accepts input data and programs and outputs data.Computer System Solve problems and interact with their environment. They consist of Devices, programs, and data.Program Is a set of instructions executed sequentially that tells the computer what to do with data.Chapter 1 IntroductionVon Neumann ModellFour Subsystems MemoryMemory（内存） Arithmetic Arithmetic Logic Logic UnitUnit（ALU ALU ，算术逻辑单元） Control Unit Control Unit（控制器） Input/Output Input/Output（输入/输出设备）lStored Program ConceptlSequential Execution Of InstructionsChapter 2 Data RepresentationData TypeslText BytelNumber ASCIIlImage Bitmap，Vector，Pixel，ResolutionlAudio Digital，AnaloglVideo FrameChapter 2 Data RepresentationTextlBit （位） A bit (binary digit) is the smallest unit of data that can be stored in a computer，it is either 0 or 1. lBit Pattern（位组合格式） A bit pattern is a sequence, or as it is sometimes called, a string of bits that can represent a symbol. lByte（字节） A bit pattern of length 8 is called a byte. Chapter 2 Data RepresentationNumberlASCII American Standard Code for Information Interchange (ASCII)（美国信息交换标准代码）. This code uses 7 bits for each symbol. This means 128 different symbols can be defined by this code.Chapter 2 Data RepresentationImagelBitmap Graphic Pixel: Picture elementsResolution: The size of the pixelChapter 2 Data RepresentationImagelVector Graphic An image is decomposed into a combination of curves and lines. Each curve or line is represented by a mathematical formula.Chapter 3 Number RepresentationConcepts Decimal system (十进制十进制) based on 10，0-9； Binary system (二进制二进制) based on 2，0-1； Octal notation (八进制八进制) based on 8，0-7； Hexadecimal notation (十六进制十六进制) based on 16 ，0-9，A-F。Chapter 3 Number RepresentationConversionConversion Decimal Binary Hexadecimal notation Octal notationChapter 3 Number RepresentationInteger Representation Unsigned Integer（无符号整数）（无符号整数） Overflow（溢出）（溢出） Sign-and-Magnitude Format（原码）原码） +0 00000000 -0 10000000Range: 0 . (2N-1)Range: -(2N-1-1) +(2N-1-1)Chapter 3 Number RepresentationInteger Representation Ones Complement Format（反码反码） +0 00000000 -0 11111111 Twos Complement Format（补码）补码）Range: -2N-1 +(2N-1-1)Range: -(2N-1-1) +(2N-1-1)Chapter 3 Number RepresentationExcess System Magic Number Is normally (2N-1) or (2N-1-1), where N is the bit allocation. Example: Represent 25 in Excess_127 using an 8-bit allocation. -25 + 127 102 1100110 01100110Chapter 3 Number RepresentationFloating-Point Representation 1. Convert the integer part to binary. 2. Convert the fraction to binary. 3. Put a decimal point between the two parts.Example: Transform the fraction 0.875 to binary0.875 1.750 1.5 1.0 0.0 0 . 1 1 1Chapter 3 Number RepresentationNormalization Example: Show the representation of the normalized number + 26 x 1.01000111001 6 + 127 133 10000101 Sign exponent mantissa -+1010001.1101-111.000011+0.00000111001-001110011- 6 26 3 Normalized - +26 x 1.01000111001 -22 x 1.11000011 +2-6 x 1.11001 -2-3 x 1.110011Chapter 4 Operations on BitsArithmetic Operations Example1: Solution: Add two numbers in twos complement representation: (+24) + (-17) (+7)Carry 1 1 1 1 10 0 0 1 1 0 0 0 1 1 1 0 1 1 1 1-Result 0 0 0 0 0 1 1 1 +7Chapter 4 Operations on BitsArithmetic Operations Example2: Solution:Add two numbers in twos complement representation: (+127) + (+3) (+130)Carry 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 0 0 0 0 0 0 1 1 -Result 1 0 0 0 0 0 1 0 -126(Error)An overflow has occurred. Chapter 4 Operations on BitsArithmetic Operations Example3: Solution: Subtract 62 from 101 in twos complement: (+101) - (+62) (+101) + (-62)Carry 1 10 1 1 0 0 1 0 1 1 1 0 0 0 0 1 0-Result 0 0 1 0 0 1 1 1 39The leftmost carry is discarded.Chapter 4 Operations on BitsLogical OperationsChapter 4 Operations on BitsLogical OperationsExample1:Solution:Use the NOT operator on the bit pattern 10011000.Chapter 4 Operations on BitsLogical OperationsExample2:Solution:Use the AND operator on bit patterns 10011000 and 00110101.Chapter 4 Operations on BitsLogical OperationsExample3:Solution:Use the OR operator on bit patterns 10011000 and 00110101.Chapter 4 Operations on BitsLogical OperationsExample4:Solution:Use the XOR operator on bit patterns 10011000 and 00110101.Chapter 4 Operations on BitsLogical OperationsExample5:Solution:Use a mask to unset (clear) the 5 leftmost bits of a pattern. Test the mask with the pattern 10100110.ANDChapter 4 Operations on BitsShift Operations Shift operations can only be used when a pattern represents an unsigned number. 左移：左移： *2 右移：右移： / 2Chapter 5 Computer OrganizationMain Memory-Kilobyte(K)Megabyte(M)Gigabyte(G)Terabyte(T)Petabyte(P)Exabyte(E)-210 bytes220 bytes230 bytes240 bytes250 bytes260 bytes-103 bytes106 bytes109 bytes1012 bytes1015 bytes1018 bytesKB Kilobyte：千字节，1024字节MB Megabyte：兆字节GB Gigabyte：十亿字节TB Terabyte：1000吉千兆字节GB；兆兆位Chapter 5 Co
