CS255 Syllabus & Progress

Material covered are displayed in blue.

Intro to CS255:

Logistics:

Part 1: Fundamental knowledge of the Computer

Intro to the Computer
- What exactly is a "computer" ? click here ---
- What the inside of a computer looks like: click here (show pictures) ---
- Functional/logical structure of the computer:
  - Logical components of a computer and their functions: click here ---
  - What does the computer system do: click here ---
  - What does the peripheral devices do for the computer system: click here ---
- Inter-connecting the various parts of the computer: click here ---
The computer memory (RAM):
- Computer memory and binary digits (bits): click here --- --------------------------------- 1/18
- Combining consecutive memory cells tomake larger memory cells: click here ---
- Data transfer between CPU and memory: click here ---
  - Watch an insighful YOUTUBE video on computer memory
- The effect of the number of wires in the data bus and address bus: click here ---
Storing information using Binary numbers (codes + context = information):
- Intro to number systems: click here ---
- Representing information using codes - brief introduction: click here ---
- How computers store/represent (non-numerical) information: click here ---
The different types of codes used in a computer system to represent various kinds of information
Storing Boolean data inside a computer
- Overview of the codes used for data types in programming languages: click here --- --------------------------------- 1/23
- Storing Boolean values inside the computer: click here ---
Representing and storing unsigned integer (= whole) numbers inside a computer
- Representing unsigned integral values inside the computer:
  - Unsigned numeric values: click here ---
  - The decimal and binary number systems: click here ---
  - Converting between dec <--> bin and storing unsigned (integer) values in program variables: click here ---
  - Arithmetic with binary numbers: click here ---
- Other number systems that are related to the Binary number system (condensed representation of bit patterns):
  - Octal numbers: click here ---
  - Hexadecimal numbers: click here ---
Homework 1: computer architecture click here
Representing and storing signed integer (whole) numbers inside a computer
- Representing (and storing) signed integral values inside the computer:
  - Introduction to signed integer (whole) values: click here ---
  - The signed-magnitude representation for signed integer (whole) values: click here --- --------------------------------- 1/25
  - Prelude to 2's complement code - the 10's complement encoding: click here
    - --- - Intro to 10s complement encoding
    - --- - Mapping 3 digit 10s complement code to signed values
    - --- - What can the 10s complement code do for us and why it works
    - --- - Encoding and decoding 10s complement codes
    - --- - The alternate reality created by the 10s compl code and the overflow phenomenon
  - The 2's complement number encoding:
    - How are signed numbers encoded inside the computer (2's complement code): click here
      - --- - Intro to 2s complement encoding
      - --- - Encoding and decoding 2s complement codes
    - Compile-time support for the int, short and byte data types: click here --- --------------------------------- 1/30
    - Converting between the different integer types (int, short and byte): click here ---
  - The "Excess-n" codes: an alternate binary encoding for signed values: click here ---
Representing and storing fractional numerical values inside a computer:
- Fixed point binary numbers: click here ---
- Floating point numbers
  - Floating point binary representation: click here ---
  - Floating point round off error: click here ---
Homework 2 re-enforces number system concepts: click here
Representing and storing text data inside the computer
- ASCII code: click here ---
- Unicode: click here --- --------------------------------- 2/1
Input and output operations in a computer program
- Human <==> Computer communication (explains the need for conversion from ASCII to other representation and vice versa):
  - Introduction: keyboard input and terminal output devices click here ---
- Boolean input and output: (converting between ASCII representation of Boolean values and the 0/1 boolean code)
  - Pre-requisite: Java Strings click here ---
  - How to enter Boolean inputs - converting between ASCII String representation and Boolean representation: click here ---
  - How computers print out Boolean outputs - converting between Boolean representation to ASCII String representation: click here ---
- Numeric (integer) input/output: (converting between ASCII representation of integer numbers and the 2's complement code)
  - Introduction: click here ---
  - Java pre-requisites for String <==> Integer conversion:
    - The compiler translates every number in your program into a 2s complement binary representation: click here ---
    - Computing (calculations) with ASCII codes in Java: click here ---
    - The charAt( ) method and a final reminder/review: click here ---
  - How to enter integer inputs - Conversion algorithm ASCII representation -> 2's complement representation:
    - Intro: what is the problem when you enter an integer number ? click here ---
    - The trivial (but not-practical) solution: click here ---
    - Converting a string of 1 digit integer to 2's complement representation: click here ---
    - Converting a TWO DIGIT decimal integer string to 2's complement representation click here ---
    - Converting any decimal integer string to 2's complement representation click here ---
  - How computers print out integer values - Conversion algorithm 2's complement representation -> ASCII representation :
    - Intro: what is the problem when the program prints an integer number ? click here ---
    - The trivial (but not-practical) solution: click here ---
    - Converting a 1 digit decimal number to ASCII representation: click here ---
    - Converting a TWO-digits decimal number to ASCII representation: click here ---
    - Converting any decimal number to ASCII representation: click here --- --------------------------------- 2/6
    (My old notes on conversion algorithms: click here)
Homework 3 re-enforces string ⟷ int conversion: click here
Representing computer instructions inside the computer (intro to hardware):
- Intro: what kinds of instructions can a computer execute ? click here ---
- Encoding computer instructions: click here ---
- Fixed length (RISC) vs. variable length (CISC) instruction formats: click here ---
- FYI: Sample instruction encodings (if you want to know more about how some manufacturers encode their instructions) - not covered in class:
  - M68000 Instruction encoding: click here -- no slides, read for your own interest
  - ARM Instruction encoding: click here -- no slides, read for your own interest
- Watch a YOUTUBE video on instruction set (watch for yourself, not shown in class)
Part 2: C programming
Introduction to C for Java programmers
- How a CS professional should learn a new programming language: click here ---
- Intro to C programming:
  - Comparing C and Java: click here ---
  - The Hello World program in C: click here ---
  - The arguments of the main( ) function: click here ---
  - Basic input/output operations in C ---
    - Printing values of the built-in data types: click here
    - Reading in values of the built-in data types: click here
  - Things that are identical in Java and C click here ---
  - Things that are different in Java and C (slides only) ---
The C Pre-processor:
- Intro: click here ---
- Comments in C (/* ... */ or // ... ): click here ---
- Macros (#define): click here ---
- Including files (#include): click here --- --------------------------------- 2/8
- Conditional pre-processing: click here ---
- Trick to prevent a file being included multiple times (and break the recursive include chain): click here ---
I will first discuss language features that are similar in C and Java to get you programming in C quickly.
First: some things in C that you must be always remember (very different from Java):
- C is not a OOP language:
- Automatic type conversions in C:
- The C-compiler is a 1-pass compilers and Java-compiler is a 2-pass compiler:
C's data types and variables:
- C's built-in data types: (with highlight on the unsigned type) click here ---
- Defining variables in C (local and global variables): click here ---
- Declaring global variables: click here ---
- Another way to define constants: the const data type modifier: click here ---
High level operators (quick review - they are same as Java):
- Arithmetic Operators: ( +, -, *, / ): click here ---
- Assignment Operators: click here ( +=, -=, *=, /=, &=, |=, ~=, >>=, <<= ) ---
  - Assigning values from different data types to a variable: click here ---
- Increment/decrement Operators: click here ( ++, -- ) ---
- Boolean data type and operations:
  - The Boolean data type and Boolean values in C: click here ---
  - Compare and Logic Operators: ( <, <=, >, >=, ==, !=, &&, ||, ! ) click here ---
- The conditional operator ?: click here ---
- The comma operator , click here ---
- The sizeof operator click here ---
- Priority and Associativity of the C operators click here --- --------------------------------- 2/13
Statements (quick review - they are same as Java):
- Assignment Statement: click here ---
- Selection Statements (if, if-else, switch): click here ---
- Loop Statements (while, for, do-while): click here ---
- Sample C programs: --- only
Homework 4 introduces you the features in C that are similar to Java by writing 2 C functions click here
Arrays: (C has static arrays, Java has dynamic arrays)
- Defining and using one-dimensional array variables: click here ---
- Concepts: static and dynamic arrays: click here ---
- Run time Array bound checks: click here ---
- Using arrays: find the smallest element and shift left --- only
- Defining and using two-dimensional array variables: click here ---
- Declaring (global) array variables: click here --- --------------------------------- 2/15
Functions (= methods):
- Defining and calling a function in C: click here ---
- The Parameter passing mechanism of C: click here ---
- Passing a different type of values as specified as parameter in function calls:
  - Calling a function using a different type of value than the specified data type: click here ---
  - Difference in type conversion in function calls between C and Java: click here ---
- Function declarations and their scope: click here ---
  - Implicit function declaration (only) in C: click here ---
- Array parameters click here ---
- Using array parameters: the selection sort: --- only
- No function overloading in C !!!! click here ---
Debugging techniques for C programs: (debugging will not be covered in tests)
- Using the gdb debugger to find the crash location: click here --- --------------------------------- 2/20
- Debugging with printf: click here ---
Multi-files C programs - the importance of declaring functions:
- Introduction to multiple file compilation: click here ---
- How to compile a multiple files C program: click here ---
- The importance of function declaration in multi-file C programs: click here ---
- Declaring function using header files: click here ---
The make (UNIX) utility: (Make will not be covered in tests)
- File dependencies in the compilation process: click here ---
- Structure of "make files": click here ---
- A simple makefile: click here ---
- Example of makefile for a multi-file C program project: click here ---
Low level operators:
- Bit-wise-Operators: (used in CS350)
  - The bit-wise operators: ( &, |, ^, ~ ) click here ---
  - How to use the bit-wise operators - introduction click here ---
  - Denoting bit patterns using values in base 2, 8 and 16: click here ---
  - Bit manipulation operations - set a bit, clear a bit, flip a bit and test a bit: click here --- --------------------------------- 2/22
- Shift-Operators: (used in CS350) click here ( >>, << )
  - Intro: click here ---
  - Set bit at position n: click here ---
  - Clear bit at position n: click here ---
  - Flip bit at position n: click here ---
  - Test bit at position n: click here ---
- How to implement a "bit" array using an array of int click here ---
Homework 5 reinforces bit operations and using a bit array click here

Language features that are both available in C and Java but differ slightly
User-defined types in C (i.e.: structures)
- Defining and using struct type and variables: click here ---
- typedef: giving a (shorter) name to struct click here ---
- Always use header files to store the struct's and typedef's in your C program: click here ---
- Declaring (global) struct variables: click here ---
- struct parameter variables are passed-by-value: click here ---
- Size of a struct "object": click here ---
The life time and scope of the different kinds of variables in C:
- Review: Life time and Scope of the variables: click here --- --------------------------------- 2/27
- Kinds of variables in C: click here ---
- Life time of variables in C (and when is a variable initialized ?): click here ---
- Scope of variables in C:
  - Scoping rules for local and parameter variables in C: click here ---
  - Scoping rules for: (1) global, (2) static global and (3) static local variables: click here --- ---
Advanced C language features that are not found in Java (pointer data type !)
The reference data type and reference (pointer) variables
- Reference (pointer) data type and variables: click here ---
- The reference (&) operator click here ---
- Storing the result of reference (&) operator in reference data typed variables: click here ---
- Using reference variables --- the dereference (*) operator: click here ---
- Function with reference variables as parameters --- passing parameters by-reference: click here --- --------------------------------- 2/29
Pointer to a user-defined type:
- Pointer to user-defined (struct) variables: click here ---
- The short-hand operator ->: click here ---
Using pointers to create and maintain linked lists in C:
- Review of linked lists (data structure) click here ---
- Introduction to linked lists in C: click here ---
- Memory management - you must de-allocate list elements when you delete them !!! click here ---
- Traversing a linked list: ---
- Inserting at the front of a list: click here ---
- Inserting at the end of a list: click here --- --------------------------------- 3/5
- Delete at the front of list: click here ---
- Delete at the end of list: click here ---
  Homework 6 reinforces linked list click here
Pointer arithmetic and accessing array elements
- Pointer arithmetic: click here ---
- Accessing arrays using pointer arithmetic : click here ---
- The [ ] operator: click here ---
- Implementing dynamic arrays in C: click here ---
- The ++ and -- operators on pointers - traversing an array: click here ---
- Postscript: a[] and *a --------------------------------- 3/7
Strings in C:
- There is no "strings" in C --- it's just an array of char (ending with a NUL character): click here ---
- Some Strings functions in C Standard library click here ---
Homework 7 shows you how write a "class" in C -- it's all about organization using header files and C program files click here

C documentations:
- The C programming language book - Kernighan and Richie: click here
- The C99 standard: click here
- Obituary of Dennis Ritchie (co-inventory of C): click here
Part 3: Assembler Programming (complete understanding of how a computer works)
Prelude to assembler programming: internal details of the CPU
- The structure of the Central Processing Unit (CPU): click here ---
  - How the CPU uses the general purpose registers: click here (***) ---
  - How the CPU uses the special purpose registers (Program flow): click here (***) --- --------------------------------- 3/12
- The Instruction Execution Cycle of the CPU: click here --- (I kept an older page: click here)
  - Instruction Execution Cycle - in order program flow: click here (***) ---
  - Instruction Execution Cycle - out-of-order program flow (branching): click here (***) ---
Intro to assembler programming using the ARM processor
- A historical introduction to programming languages: click here ---
- Prelude to assembler programming - get to know your CPU !!! click here ---
- The ARM processor's CPU architecture:
  - The registers of the ARM processor: click here ---
  - EGTAPI's display of the registers: click here ---
- The "Hello World" program in assembler programming language: click here --- --------------------------------- 3/14
- Program organization illustrated using the "Hello World" assembler program with the help of EGTAPI: click here ---
- Labels in Assembler Programming: click here ---
The text and data assembler program sections/segments
- The (program) text section/segment of an assembler program (and labels): click here ---
- The data section/segment of an assembler program (and labels): click here ---
- Memory alignment requirements: click here ---
Assembler programming with integer constants and simple integer variables
- Introduction (motivate using only integer data types): click here --- slides
- The mov instruction in ARM:
  - Moving a small integer value into a register: click here --- slides
  - Moving(=copying) one register into another register: click here --- slides
  - Moving a large integer value into a register: click here --- slides
  - Moving an symbolic constant (=address) into a register: click here --- slides
- Store-ordering in memory: big and little endian ordering click here --- slides
- Reading (the value stored in) a simple memory variable: click here --- slides --------------------------------- 4/2
- Writing/updating (the value stored in) a simple memory variable: click here --- slides
  - What happens when you use an incorrect load/store instruction: click here --- slides
  - The importance of data type information in the compilation process: --- slides ONLY
- Translating simple assignment statements to assembler: b = 4 and b = a click here --- slides
  
  Homework 8 re-enforces the use of move, load and store instructions: click here
- Arithmetic operations (instructions): click here --- slides
- Assignment statement with arithmetic expressions using (only) simple variables: c = a + b click here --- slides --------------------------------- 4/4
The array data structure (teach with demo/asm/3-array/demo.s)
- Intro to data structures: --- slides
- How is an array data structure stored in computer memory: click here --- slides
- Defining an array in assembler: click here --- slides
- How to access an element in an array: click here --- slides --------------------------------- 4/9
- The load and store assembler instruction formats used to access array data: click here --- slides (simultaneously use the examples in next set of slides to illustrate)
- Assembler programming examples of accessing array: click here --- slides (1) --- slides (2) --- slides (3)
- Examples with arrays: --- slides ONLY
The linked list data structure (teach with demo/asm/4-linked-list/demo1.s and demo2.s)
- How is an object stored in memory: click here --- slides
- How is a linked list stored in memory: click here --- slides (I kept my old note here: old)
- Defining and accessing the head variable in assembler: click here --- slides --------------------------------- 4/11
- Computiing offsets of fields in a (Node) variable/object: click here --- slides
- Assembler programming examples of accessing fields in a linked list: click here --- slides
Homework 9 re-enforces access technique to structured variables (arrays and linked lists): click here
- My summary notes on ARM assembler programming techniques used to prepare the CS255 material: click here
- A single sheet summary of ARM instruction nmenomic codes : click here
- Documentation - the complete ARM Instruction set and encoding (not part of syllabus material): click here
Now you know what the computer actually does when it executes an assignment statement: how it evaluates an expression and assigns the result to a variable in a high level programming language. We will discuss various program flow control structures next.
The Selection (if, if-else) Statements:
- Introduction: click here --- slides
- Branching - out of order program flow: click here --- slides
- How is the branch instruction implemented ? click here --- slides
- The Compare (cmp) and Branch (beq, bne, blt, ble, bgt, bge, bal) assembler instructions of ARM: click here --- slides
- Coding Selection statements in assembler:
  - If-statement with a simple condition: click here --- slides --------------------------------- 4/16
  - If-else-statement with a simple condition: click here --- slides
  - Compound condition using and: click here --- slides
  - Compound condition using or: click here --- slides
The Loop Statements:
- While-statment: click here --- slides
- For-statment (sum an array): click here --- slides --------------------------------- 4/18
- Traversing linked lists: click here --- slides
- Do-statement: click here. --- slides
Homework 10 re-enforces the use of compare and branching in writing your first assembler program containing a while loop and if-statements: click here

Now you know what the computer actually does when it runs a program. The only thing that you still do not know is what happens in a function call (there is still a lot to learn...).
Subroutines (a.k.a. methods, procedures, functions)
- Introduction: click here --- slides
- Leaf subroutines and Non-Leaf subroutines: click here --- slides
- Implementing Leaf subroutines in ARM assembler:
  - Implementing the subroutine call control flow using the branch instruction: click here --- slides
  - Calling a functions - ARM's bl (branch and link) instruction: click here --- slides
  - Returning from a leaf subroutine click here --- slides
- Implementing Non-Leaf subroutines in ARM assembler:
  - What happens when a called function calls another function: click here --- slides
  - The program runtime stack of a running program: click here --- slides
  - The ARM assembler push and pop instructions: click here --- slides --------------------------------- 4/23
  - Implementing non-leaf methods/functions using the program stack: click here --- slides
- Using the non-leaf function technique to implement leaf functions: click here --- slides
Leaf functions with parameters and local variables in CPU registers
- Introduction: click here --- slides
- Passing parameters to a function and passing return values using CPU registers:
  - Intro: using CPU registers to pass parameters and return values: click here --- slides
  - sumSquares(a,b): using CPU registers to pass parameters and return values click here --- slides
- sumRange(A, a, b): using registers as local variables: click here --- slides
**** The final will cover upto this point ****
Project 7 (Bubblesort) re-enforces the use of registers for passing parameters and storing local variables: click here ****** NOT ASSIGNED
Non-Leaf functions with parameters and local variables in the runtime stack
- Passing parameters and allocating local variables using the program stack:
  - Intro: using the program stack to store parameters and local variables: click here --- slides 1 --- slides 2 --------------------------------- 11/28
  - Why can the stack avoid the overwrite problem in registers: click here --- slides
  - How to code subroutine return in assembler --- tearing down a stack frame: click here --- slides
  - Summary and a "How to" guide: click here --- slides
  - A complete example of passing parameters and allocating local variables using the program stack: click here --- slides
- Another usage of the program stack - saving registers in an interrupted computation: click here --- slides

Recursive subroutines/methods: (are always non-leaf functions !)

Introduction: click here --- slides
First recursive method in assembler, the classic factorial function: click here --- slides

Second recursive method in assembler: click here --- slides

Programming project pj8 re-enforces storing parameters and local variables on stack with a recursive function: click here

I inserted some material here to help you understand recursion:

Recursion is a divide and conquer technique to solve problems:
- How to design recursive algorithms: click here --- slides
- Example of divide and conquer using recursion: click here --- slides
- A recursive insert at the tail of a list algorithm: click here --- slides

Programming project pj9 is another recursion project --- inserting a new list element in an ordered linked list: click here

Parameter passing techniques:
- Introduction: click here --- slides
- Implementing Pass-by-value and Pass-by-reference mechanism in assembler: click here --- slides
- Important note: click here --- slides
If you understand everything so far, you now know exactly what is going on when a computer executes a program. You can apply what you learn and write assembler programs in any assembler language, e.g., Intel. To program with a new chip, all you need to learn are:
I have Intel assembler programming material after the C lecture notes to demonstrate this process. (These notes are not part of the CS255 curriculum - it's "for your eyes only")

That's all, Folks !
Additional Enrichment Material: Intel 80x86 programming (not covered in CS255)
- A free Intel Macro Assembler (if you want to write assembler on your PC): RIGHT click here and SAVE AS
- An online documentation on Assembler programming with MASM: click here
- Intel Assembler Code Table: click here
- The Intel 80x86 CPU architecture: click here
- The Intel 80x86 directives: click here
- The Intel 80x86 Addressing modes: click here
- Arithmetic operations: click here
- Compare and Branch: click here
- Subroutine call and return: click here
- The Art of Assembler Language Programming book: click here
  Check out chapter 6
Rough notes on Intel Assemler programming:
- Intel registers: click here
- Intel registers: click here
- Reserving space for variables: click here
- Addressing modes (MOV): click here
- Arithmetic: click here
- CMP and Jump: click here
- Stack, procedure call/return: click here
Other resources:
- Matloff GNU assembler programming tutorial: click here
- Sourceforge GNU assembler programming tutorial: click here
- Free Intel Macro Assembler (if you want to write assembler on your PC): RIGHT click here and SAVE AS
- Intel Assembler Programming book - this book is like the CS255 course using Intel Assembler code: click here
- Step by step Windows programming tutorial shows you how to write window programs, menus, call backs, etc: click here
- The Art of Assembly Programming (a very good online book, but the 32 bit version uses a non-standard assembler called "HLA" - High Level Assemble language) click here