Introductions Name Where from Something non-academic What's the point of this class?

2. Introductions • Name • Where from • Something non-academic • What's the point of this class? • Not history, but not all cutting edge • Awesome! We get to learn a lot! • Bummer – we have to learn a lot. • Class webpage • Syllabus • use of moodle • email

3. Labs • When due • Partners • How independent • Learning C • vs. Projects – may have more than in past • Reading • Our textbook • Before/after lecture • Questions at beginning of class • Active Learning

4. C • Why is C special / different / awesome / horrible? • How does the hello world code turn into a program? • Source program (human) -> preprocessor • modified source program (human) -> compiler • assembly program (assembly) -> assembler • relocatable object programs (binary) -> linker • executable object program (binary)

5. printf.o Pre- processor (cpp) Compiler (cc1) Assembler (as) Linker (ld) hello.c hello.i hello.s hello.o hello Source program (text) Assembly program (text) Modified source program (text) Relocatable object programs (binary) Executable object program (binary)

6. printf.o Pre- processor (cpp) Compiler (cc1) Assembler (as) Linker (ld) hello.c hello.i hello.s hello.o hello Source program (text) Assembly program (text) Modified source program (text) Relocatable object programs (binary) Executable object program (binary) g++ helloWorld.c -ohelloWorld ./helloWorld

7. How does the hello world program execute? • disk  memory  register • display device

8. Memory hierarchy • Virtual addresses, heap/stack, files

9. Linux What is it? How it fits into the class….

10. Woo! • Done with chapter 1! • Only about 8 chapters to go!

11. Overflow • Number

12. Overflow • Number • Buffer • Smashing the stack for fun and profit • Phrak 49 • Generally from strcpy(), strcat(), and sprintf() • Overflow fixed size buffer with machine code

13. Bits

14. Bits • 101 • 5 in binary • 5 if it’s an integer • +∞ if float • 0x101 = 65 in dec • A if it’s hex referring to ASCII

15. Bits + Context • Integer • Float • Character • Program instruction • Memory Address • Bytes • Trivia: Nibble/Nybble

16. Background: Hexadecimal • 0xA4 • 10100100 (binary) • 164 (decimal)

17. Take out some paper… • Convert 0x173A4C to binary • Convert 11 1100 1010 1101 1011 00112 to hex • Convert 7AF16 to base-10 • Convert 6010 to base-16 • Convert 60010 to base-16

19. Linux ps command? • http://www.cheatengine.org/

22. Data Sizes

23. Byte Ordering • Big Endian: Sun, PPC, ARM, PDP-10 • Most significant byte has highest address • Little Endian: x86, x86-64, VAX, PDP-11 • Least significant byte has lowest address

24. Blame George Bool & Claude Shannon • And • Or • Not • Xor

27. `

28. Lab: give masking example • Lab: Tmin: smallest signed int

30. Unsigned Signed (typically)

35. Example program from lab1: ishow.c

36. http://www.example.com/name%20with%20spaces/http://www.asciitable.com/http://www.example.com/name%20with%20spaces/http://www.asciitable.com/

37. Ways of representing negatives?

38. The Sacrificial Bit

40. Max/Min Values (Assume using 32 bit architecture) • unsigned short int • Min • Max • signed short int • Max • Min

44. = X x +16