BIM 201 System Software

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BIM 201 System Software

• Time Wednesday 9-12
• Location B1
• Instructor Cuneyt Akinlar
• TA Cihan Kaleli
• Grading
• 2 Midterms 10 each
• Final 20
• Projects 60
• Books
• Any C book

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Whats this course about

• System software components and how they work
  together in converting your C program into a form
  that is understood by the machine
• Preprocessor
• Compiler
• Assembler
• Linker
• Loader OS

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Goals of the course

• To improve your C/C programming skills by
  having you implement a lot of code
• To have you learn the basics of system software
  components
• Preprocessor, Compiler, Assembler, Linker, Loader
  OS
• To have you learn the basics of Computer
  Architecture
• CPU, ALU, registers, instruction sets

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System Software Components

• Preprocessor (cpp)
• Removes comments, expands macros
• Compiler (gcc)
• Converts your programs implemented in high-level
  language to assembly language, which are mnemonic
  codes that correspond one-to-one with machine
  language
• Assembler (gas)
• Converts programs implemented in assembly
  language to machine language, which are binary
  number codes understood by a specific CPU
• Linker (ld)
• Combines several object files together into a
  executable
• Loader Operating System (execv Linux)
• Loads your program into memory for execution

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ExampleThrough the Preprocessor
define MACRO1 30 / Here is a comment. This
will be removed / main() int i i
MACRO1 / Set i to 30 / printf("i d,
MACRO1 d\n", i, MACRO1) / end-main /
Preprocessor (cpp)
main() int i i 30 printf("i d,
MACRO1 d\n", i, 30)
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Through the Compiler
main() int i i 30 printf("i d,
MACRO1 d\n", i, 30)
.rodata .LC0 .string "i d, MACRO1
d\n" .text main pushl ebp
movl esp, ebp subl 24,
esp andl -16, esp movl
0, eax addl 15, eax addl
15, eax shrl 4, eax sall
4, eax subl eax, esp
movl 30, -4(ebp) subl 4, esp
pushl 30 pushl -4(ebp)
pushl .LC0 call printf addl
16, esp leave ret
Compiler (gcc)
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Through the Assembler Linker
.rodata .LC0 .string "i d, MACRO1
d\n" .text main pushl ebp
movl esp, ebp subl 24,
esp andl -16, esp movl
0, eax addl 15, eax addl
15, eax shrl 4, eax sall
4, eax subl eax, esp
movl 30, -4(ebp) subl 4, esp
pushl 30 pushl -4(ebp)
pushl .LC0 call printf addl
16, esp leave ret
prinf
Object Code
Executable Code
Linker (ld)
Assembler (gas)
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Finally Operating System

• Is a layer of software that exports an easy to
  use interface to program the hardware

User Programs
P1
P2
Pn
System call API
Operating System (Windows, Linux, Solaris, )
Hardware API
Hardware

• User programs make use of the hardware through
  the services provided by the OS
• Thus OS makes life easier for user programs

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Projects 60 total

• P1 - C project to dust of your C skills 5
• P2 - Preprocessor 7.5
• P3 Emulator 7.5
• P4 Disassembler 5
• P5 Assembler 10
• P6 Compiler1 7.5
• Simple expressions
• P7 Compiler2 7.5
• If/then/else, while loops
• P8 Compiler3 10
• Function calls parameter passing

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Projects - Warnings

• You can do your projects in groups of 2 people
• If you work in groups, submit a single project,
  and write the name of both group members at the
  top of main.cpp
• If you forget to write your group members, we
  will assume that only ONE person has worked on
  the project. No excuses will be accepted after
  the project delivery. So be responsible!
• Cheaters will FAIL the class!
• We have automated tools to check for cheating.
  So, do not even think about it.