CSCI 192 Engineering Programming 2. Subject Overview

Transcription

1 CSCI 192 Engineering Programming 2 Week 1 Subject Overview Lecturer: Dr. Markus Hagenbuchner Slides by: Igor Kharitonenko and Markus Hagenbuchner Room markus@uow.edu.au UOW /07/2010 1

2 Lecture Overview What you need to know about lectures, labs, tutorials, assignments and exams. What Engineering Programming 2 is and how it is related to Engineering Programming 1 and your engineering degree. 27/07/2010 2

3 Lecturer: Lecturers Dr Markus Hagenbuchner 3 years of industry and 18 years of academic experience Machine Fitter, Liebherr, Germany Uni Ulm, Germany, AI and Machine Learning in robotics UoW, Data Mining and Machine Learning in structured domains. 66 papers and book chapters published. 27/07/2010 3

4 Tutors Wednesday Labs: Ms Angela Piper, PhD candidate Mr Ce Zhan, PhD candidate Friday Labs Mr Hooman Shidanshidi, PhD candidate Dr Markus Hagenbuchner, Senior Lecturer 27/07/2010 4

5 Method of Presentation Lectures : 2 hours per week, 13 lectures Tutorial sessions : 1 hour per week, 12 sessions starting from week 2 Laboratory sessions: 2 hours per week, 12 sessions starting from week 2 Assignments : 2-3 assignments Total : 5 contact hours This is a 6 credit point subject. According to Course Rule 003, this requiter at least 12 hour per week, including self-directed study 27/07/2010 5

6 Assessment Assessment Items Percentage of Final Mark Due Date Tutorial sessions Marks for item Lab sessions 20 marks Assignments 20 marks Final Examination 60 marks Total 100 marks Minimum % required of the item to pass subject Satisfactory attendance 40% 30% weeks 2-13 earned during weeks 3-12 as scheduled 40% exam week as per schedule 50% The mark must be 50 to pass the subject 27/07/2010 6

7 Caution CSCI192 is a follow up to CSCI191 It is delivered only in spring sessions If you fail CSCI192 in spring session you cannot study CSCI192 in the autumn session To minimise your risk, take this subject very seriously from the first week Contact the subject coordinator as soon as you feel that your progress is not good 27/07/2010 7

8 Lectures The lectures will introduce fundamental computing concepts and the principles of programming including hardware architecture, algorithm design, C, C++ and Assembly languages. The lectures will contain a sufficient number of examples and slides with animation to explain complex technical aspects. It is highly recommended that you implement the examples, compile and run the programs on your computer You are encouraged to participate actively in the lecture sessions answering quiz questions and making your own notes that facilitate your understanding. 27/07/2010 8

9 Tutorial Sessions Week 2 Week 13 Thursday 11:30-12: The tutorial sessions will be one week behind the lectures to provide sufficient time for preparation To get prepared, students need to go through lecture notes, suggested chapters of the text book and complete the questions in the textbook that are specified in the lecture notes Tutorial sheets will be distributed at the beginning of each session Students are required to complete the tutorial tasks and then participate in the discussions of the solutions 27/07/2010 9

10 Laboratory Sessions Week 2 Week 13 Lab room The laboratory sessions will be one week behind the lectures to provide sufficient time for preparation To get prepared, students need to look through lecture notes, the tutorial tasks and solutions, suggested chapters of the text book and complete the questions that are specified in the lecture notes Lab tasks are available online and can be completed before the laboratory sessions Students are required to complete the lab tasks within the first 80 minutes of the 2 hour lab session and show the solution to the tutor for marking The marks are given according to the number of tasks completed and understanding of the material covered ( see CSCI192 Subject Outline for more details ) 27/07/

11 First Laboratory Session Week 2 Go to the laboratory room Wednesday lab: 14:30-16:30 Friday lab: 13:30-15:30 You must be enrolled in exactly one of these labs. Tasks will be: -Debugging - Review of common programming errors ( from CSCI191 ) 27/07/

12 Assignments There will be 2-3 programming assignments worth a combined 20% When an assignment is released, download the assignment description from the subject website. Read carefully the design specification and make sure you understand what you are required to do ( attend a consultation if needed ) Your completed solutions must be submitted electronically via an online submission system. No submission via will be accepted One week is allocated for submitting each assignment Exact time after which the submitted assignment will not be accepted by the system will be indicated in every assignment specification Late assignments will not be accepted without a granted special consideration ( see CSCI192 Subject Outline for more details ) 27/07/

13 Self-directed Study Download lecture notes from the subject website, print a copy and look through the lecture notes prior to a lecture Attend the lecture, taking notes and adding explanations on the printed copy Read related chapters in the textbook together with lecture notes and attend consultations for clarification if required Keep all lecture notes, assignment, tutorial and lab task solutions in one folder that can be a very useful collection of materials for exam preparation 27/07/

14 CSCI192 Website The site contains the following sections: - Subject Outline - Lecture Notes -Assignments - Laboratory Sessions - Resources The Web site is the subject s Notice Board. All important notices related to CSCI192 will be posted there 27/07/

15 Subject Materials Textbook: Jeri. R. Hanly, Elliot B Koffman, C Program Design for Engineers. It may be purchased from the UniCentre bookshop. Lecture notes: The lecture notes will be available on the subject website. Students are encouraged to print their copies. The lecture notes may not include all examples and animations given in lectures 27/07/

16 Consultation Times Dr Markus Hagenbuchner Tuesday 14:30 16:30 Thursday 10:30 11:30 and 12:30 13:30 27/07/

17 Emergency Evacuation Procedure Leave the building immediately via the nearest exit Do not re-enter the building until advised Assembly areas: Lectures & Tutorials Labs 27/07/

18 Engineering Programming II Overview: What the focus of this subject is What topics are included and why How the acquired skills can be useful for your engineering degree 27/07/

19 CSCI191 Outcomes Having completed CSCI191, students are expected to: develop moderately complex C programs according to design specifications structure their programs in readable and reusable modules 27/07/

20 Programming languages Quiz: There exists literally hundreds of programming languages. Name a few Why did we decide to use C as a basis for this subject? Provide some reasons 27/07/

21 C Compilation Model (review) CSCI191 focus However, correctly written C programs need to be properly converted into binary executable files to optimise your program you need to understand how it interacts with the operating system and hardware in some situations, programming languages other that C can be more efficient you may be involved into a multi-language software project gcc ansi Wall main.c 27/07/

22 C Compilation Process gcc o tedit ansi Wall tedit.c I /usr/include L /usr/lib lm Driver: gcc Pre-processor: gcc is a set of tools cpp o tedit.i tedit.c C Compiler and Optimiser: cc1 o tedit.s tedit.i Assembler: as o tedit.o tedit.s Linker: 27/07/2010 ld o tedit tedit.o -lm 22

23 C Compilation Process To see messages produced at all compilation stages use v option $ gcc o hello.exe v ansi Wall hello.c Reading specs from /usr/lib/gcc-lib/3.2.2/specs Configured with:../configure prefix= GNU CPP version (i386 Linux/ELF) GNU C version cc1 lang-c -o /tmp/cc2dfr.s GNU assembler version as V Qy o /tmp/cc2dfr.o /tmp/cc2dfr.s /07/

24 Pre-processor C pre-processor is a program usually called cpp gcc calls cpp passing to it all relevant options -I -Wcomments cpp - takes a C source file and handles all pre-processor definitions: #include, #define, #pragma, etc. - removes all comments it produces a pre-processed C source file *.i You can invoke it explicitly and stop further processing gcc o tedit.i E tedit.c 27/07/

25 Pre-processed Source File hello.c #include <stdio.h> int main(void) { printf("hello World\n"); /*display a message*/ return 0; } hello.i typedef unsigned char u_char; typedef unsigned short int u_short; extern int getc (FILE * stream) ; extern int printf ( const char * restrict _format) ; int main(void) { printf("hello World\n"); return 0; 27/07/ }

26 C Compiler and Optimiser C compiler is a program usually called cc1 gcc calls cc1 passing to it all relevant options -ansi Wall O1 cc1 - takes a pre-processed C source file *.i and translates it into assembly language - produces an assembly language source file *.s You can invoke it explicitly and stop further processing gcc S tedit.c 27/07/

27 Assembly Source File hello.i extern int printf ( const char * restrict _format) ; int main(void) { printf("hello World\n"); return 0; } hello.s.lc0:.string "Hello World\n".text main: pushl %ebp movl %esp, %ebp call printf movl $0, %eax ret 27/07/

28 Assembler Assembler is a program usually called as gcc calls as passing to it all relevant options -Xassembler as - takes an assembly language source file and translates it into machine language binary codes - produces an object file *.o You can invoke it explicitly and stop further processing gcc c tedit.c 27/07/

29 Object File hello.s.lc0:.string "Hello World\n".text main: pushl %ebp movl %esp, %ebp call printf movl $0, %eax ret hello.o printf Library Function call 27/07/

30 Linker Linker is a program usually called ld gcc calls ld passing to it all relevant options -L -l ld - takes object files, required libraries and links them together - produces an executable file in a format that the operating system supports You can invoke it explicitly gcc o tedit.exe tedit.o -lm 27/07/

31 ELF ELF is a binary executable file standard supported by UNIX/Linux operating systems It contains several sections ELF header.text.rodata.bss.data... readelf S a.out Auxiliary information Processor instructions constants, string literals un-initialised data initialised data Displays information about ELF file a.out size A a.out Displays size of the ELF file segments 27/07/

32 Program Loading Hard Drive Computer Memory ELF Operating System Loader Stack Heap Un-initialised Data Initialised Data Instructions 27/07/

33 Memory Layout of a C program #include <stdio.h> C Source Code int addnumbers( int a, int b); Loaded C Program Stack int array1[100]; int array2[100] = { 3, 7, 15, -4 }; int main(void) { int result, num1, num2=7; int array3[100]; num1 = 5; result = addnumbers(num1, num2); return 0; } int addnumbers( int a, int b) { return (a+b); } Heap Un-initialised Data Initialised Data Instructions 27/07/

34 Program Execution Shell $ a.out $ Execution begins here Control returns to Shell Linux Start-up code stdlib Shutdown code main( ) is called printf( ) scanf( ) fprintf( ) return 0 Your program main().data.bss stack 27/07/

35 Conclusions To write efficient programs, besides sound knowledge of C language you need to understand: - memory allocation and management issues - interaction between instructions and data - basic machine codes - fundamentals of microprocessor architecture - the process of converting data and C statements into binary form 27/07/

36 Quiz Is gcc a single program or a package? What is the difference between *.c and *.i files? Are *.s files text or binary files? Are *.o files text or binary files? What is incomplete in *.o object files? What is the difference between object and executable files? Are data and computer instructions mixed inside one memory segment? 27/07/

37 Binary Numbering System Programmer int a = 5; Computer Most of the time, conversion between decimal and binary numbering systems is carried out by computers You may need to use binary numbering system to represent data in the following situations: - direct access to computer or external hardware - bit-wise operations - system software development 27/07/

38 Binary vs. Decimal The decimal system uses ten symbols to represent numbers Symbol set: The binary system uses two symbols to represent numbers Symbol set: 0 1 Example: one 1 1 two 2 10 tree 3 11 four /07/

39 Other numbering systems Other numbering systems used in computer science are octal and hexdecimal. Octal: the basis is 8, the symbols used are 0, 1, 2, 3, 4, 5, 6, 7. Is not used anymore. Hexdecimal: the basis is 16, the symbols used are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F Example: FF /07/

40 Binary vs. Decimal Apart from symbol sets, there is no conceptual difference between decimal and binary systems Both systems are positional Example: hundreds tens ones five hundred thirty four: = 5* * * is a base A weight of each symbol depends on its position Hundred: In old-english "hund" means "tens", "rad" means "number" 27/07/

41 Binary vs. Decimal Binary number Example: eights fours twos 1011 ones 1011 = 1* * * *2 0 2 is a base A weight of each symbol depends on its position The binary system and binary arithmetic was invented by Gottfried Leibniz and published in 1701 in Paris. The first computer utilising the binary system was built in 1946 at the University of Pennsylvania. 27/07/

42 Binary system A computer memory consists of a set of switches called bits which can be in one of the two states on and off. This means that a bit can store at most one value at a time, and the value can either be 0 or 1. A set of bits is needed in order to store values larger than 1. For example, a set of 8 bits is called a byte which can hold the value of 256 different combinations of 8 on and off values. Thus, all computations in a computer system are based on the binary system. 27/07/

43 Binary to Decimal conversion Binary number = 1* * * * * * = = = = = = = = = 1* *8 + 1*2 + 1*1 = 43 27/07/

44 Quiz Aside of binary and decimal, what other numbering systems are used in computer science? Convert to decimal 0000 = 1000 = 1111 = 0*8 + 0*4 + 0*2 + 0 = 0 1*8 + 0*4 + 0*2 + 0 = 8 1*8 + 1*4 + 1*2 + 1 = = = = = = = = = /07/

45 Decimal to Binary conversion Conversion from binary to decimal: repetitive multiplication and addition Conversion from decimal to binary: repetitive division by 2 and subtraction Example: Convert 23 to binary 23 / 2 = 11 and the remainder = 1 11 / 2 = 5 and the remainder = 1 5 / 2 = 2 and the remainder = 1 2 / 2 = 1 and the remainder = 0 1 / 2 = 0 and the remainder = = STOP Result 27/07/

46 Quiz Convert to binary: 5 The result 5 / 2 = and the remainder = 2 / 2 = and the remainder = / 2 = 0 and the remainder = We can STOP here Convert to binary: 9 The result 27/07/

47 Binary Addition Addition is carried out on individual bits taking into account carry bits Basic rules: = = = 10 Example: Carry /07/

48 Signed Binary Numbers Signed binary numbers are represented in two's complement format unsigned format: 5 = 101 two's complement: 5 = 0101 two's complement: -5 = 1011 an extra bit is required to represent a sign To change a negative unsigned binary number to its two's complement format: 1. Write down its binary representation ignoring a sign: Attach an extra zero at the left: Invert the number( change 0 to 1 and 1 to 0): Add 1 to the number: /07/

49 Binary Subtraction When binary numbers are represented in two's complement format, subtraction is carried out as addition with a negative number = 13 + (-10) = > > in two's complement > > in two's complement (-10) > 3 27/07/

50 Storing Integral Numbers char ASCII codes and numbers in the range [-128 to 127] Format: 8 bits two's complement binary > > > -1 unsigned char numbers in the range [0 to 255] Format: 8 bits unsigned binary > > > /07/

51 Storing Integral Numbers short int numbers in the range [ to ] Format: 16 bits two's complement binary > > > -1 unsigned short int numbers in the range [0 to ] Format: 16 bits unsigned binary > > > /07/

52 Storing Integral Numbers int numbers in the range [ to ] Format: 32 bits two's complement binary > > > -1 unsigned int numbers in the range [0 to ] Format: 32 bits unsigned binary > > > /07/

53 Commonly Used Definitions A bit: A byte: A word: 0 or bit 6 Bit 7 or the most significant bit... bit 2 bit 1 Bit 0 or the least significant bit The high byte The low byte 27/07/

54 Overflow A result of binary arithmetic operations may propagate into the sign bit Example: char result, num1 = 65, num2=67; result = num1 + num2; printf("the result is %d", result); /* is it 132? */ No errors reported A carry bit =1 turns the result into negative > /07/

55 Overflow A result of binary arithmetic operations may fall outside the range Example: unsigned char result, num1 = 130, num2=131; result = num1 + num2; printf("the result is %d", result); /* is it 261? */ No errors reported A carry bit =1 is lost > 5 27/07/

56 Caution C does not provide an implicit type conversion between signed and unsigned data Example: unsigned char result; char num1 = 100, num2=120; result = num1 - num2; printf("the result is %d\n", result); Output: The result is 236 However: printf("the result is %d\n", (char)result); Output: The result is /07/

57 Hexadecimal Numbers Large binary numbers are cumbersome to read Conversion of Decimal numbers into binary is not so straightforward Hexadecimal numbers are usually used to represent binary numbers The hexadecimal numbering system is based on 16 (hexadec is 16 in ancient Greek) Hex 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F Dec 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 27/07/

58 Hexadecimal Numbers Hexadecimal Binary A 1010 B 1011 C 1100 D 1101 E 1110 F 1111 Each digit in a hexadecimal number represents 4 binary bits Hex: 8C Bin: Hex: 47 Bin: C language syntax int num1 = 1765; /* decimal */ int num2 = 0x1765; /* hexadecimal */ 27/07/

59 Example A software driver controls communication with Intel 8251 interface chip. The control register has 8 bit that are responsible for enabling/disabling different modes. bit 0: 1 transmission enabled, 0 disabled bit 2: 1 reset previous errors bit 5: 0 generate RTS signal bit 7: 1 enable search Declare a variable of type unsigned char that stores an initial value of the control register: A E unsigned char controlreg = 0xAE; 27/07/

60 Quiz The maximum value of a char type variable is: What is the corresponding hexadecimal value? > 7F Declare a constant HIGHLIMIT equal to the maximum hexadecimal value of the char type #define HIGHLIMIT 0x7F 27/07/

61 Conclusions A program design specification may include values represented in binary format It is easier to convert binary numbers into hexadecimal format rather that into decimal You can specify values of variables in your program directly in hexadecimal format starting them with 0x... Unsigned and signed numbers are stored in different binary formats: unsigned char and unsigned int unsigned binary char and int binary two's complement Incorrectly used unsigned and signed variables produce incorrect results 27/07/

62 Suggested Exercises What are the values of the numbers represented in binary two's complement format? What are their hexadecimal equivalents? Show how this subtraction is carried out in binary form: char result, num1 = 7, num2 = 14; result = num1 num2; What is the output and why: unsigned char result, num1 = 7, num2 = 14; result = num1 num2; printf(" Result = %d\n", result); 27/07/