CSC231 Schedule 2012

--D. Thiebaut 11:15, 24 August 2012 (EDT)

---

Misc. Links & Information

• NEW: All the class demo files, as of 12/12/12
• nasmld script
• Things to remember while programming in assembly
• The NASM Manual (http://alien.dowling.edu/~rohit/nasmdoc0.html)
• Paul Carter's assembly language tutorial. Paul Carter's page can be found at http://www.drpaulcarter.com/.
• The Art of Assembly Language. It assumes a different assembler, and hence a different syntax, but has a lot of very good information.
• The Pentium Instruction Set on Wikipedia.
• Programming the Arduino in assembly.

Weekly Schedule

Week	Topics	Reading
Week 1 9/7	Friday Syllabus Class accounts The main players for this semester: PC Processor Memory Disk First program in assembly: recognize the different elements: Structure Presentation Documentation Skeleton program Hello World! on Linux (and its Mac version) Homework #1 Due Monday 9/10/12, 11:00 a.m.	Reading Chapter 1 in the Art of Assembly. Also Chapter 3, Sections 0 to 3.1.2. Sections 1.3.1, 1.3.2, 1.3.3, 1.3.4, and 1.3.5 in Carter's PC Assembly Language.
Week 2 9/10	Monday Review of Hello World Q&A Mini Lab #1 to get everybody up to speed. Wednesday Printing a box (solution for Mini Lab #1) solution programs and discussion 2 possible solutions Generating a listing with "-l" (minus ell) Hexadecimal listing of the memory contents Friday Hexdump of the executable Counter-intuitive results (size of the executables vs. size of the code + data) Exercise: recreating a program from its hexdump Mini Lab #1 Homework 2 & solution programs	Reading
Week 3 9/17	Monday Q&A ASCII Table, for reference Review of hexadecimal system (counting + adding) Wednesday Get the list of all the assembly programs seen in class: ls -ltr ~231a/handout Get one of the files into your 231a-xx account: getcopy movStrings1.asm Or use sftp sftp 231a-xx@beowulf.csc.smith.edu (and then use put filename or get filename to transfer files) Architecture of a simplified Pentium: Registers ALU CU Address and Data buses The mother of all instructions: MOV (covered here) byte, word, double-word variables. Friday Transferring information from and to memory. Example of various mov instructions Exercises with moving strings Homework #3 and Solutions	Reading The mov instruction Basic Computer Organization, Sections 3.0, 3.1, 3.3.1
Week 4 9/24	Monday Q&A Solutions to HW #2 posted (see above). The ADD instruction int a = 3, b = 5, result = 0; result = a + b; Tutorial on using the DDD debugger Wednesday Computing Fibonacci terms: Fibn = Fibn-1 + Fibn-2 with double-words with words with bytes Java's primitive data types SUB, INC, DEC, NEG Friday AND, OR, XOR, NOT (review Boolean Algebra) range of unsigned byte, words, dwords, and quadwords. Homework 4 and solution programs	Reading Sections 2.2, 2.2.1, 2.2.2, 2.2.3, and 2.2.4 in the Nasm Manual Sections 3.1 to 3.2.1 in the Nasm Manual The INC instruction.
Week 5 10/1	Monday Review of two-bit Adder The AND, OR, and INVERTER logic gates in one pdf Schematics from NASA, and a specific sheet showing logic gates. Schematics of 2-bit Adder AND, OR, XOR, NOT (review [Boolean Algebra]) range of unsigned byte, words, dwords, and quadwords. Wednesday Mini problem of the day: Assume you want to swap the top 16 bits of eax with its lower 16 bits. How can you do this? Exercises with Signed Numbers Playing with int overflow in java: MultBy3.java Same with Python: multBy3.py Friday Review of 2's Complement: Exercise in need of a solution... Extending the sign from byte to word, or word to double-word. CBW: The CBW (convert byte to word) instruction copies the sign (bit 7) in the source operand (AL) into every bit in the AH register. CWDE: The CWDE instruction copies the sign (bit 15) of the word in the AX register into every bit position of the high word of the EAX register. Masking with AND, OR, and NOT, an example Homework 5 and solutions.	Reading Section 3.2 on Bit operations (AND, OR, NOT, XOR) in Carter's eBook. Look at the section that follows on bit manipulation in C. The same operations are also supported in Java. Logical Operations on Bits, and Signed and Unsigned Numbers in the Art of Assembly reference. The CBW & CWDE instructions in the Art of Assembly reference.
Week 6 10/8	Monday: Fall Break Wednesday Bitwise operators vs logical operators in Java. Example More Addressing modes: base/indirect base/indirect with diplacement base/inderect indexed base/indirect indexed with displacement The Loop instruction. Exercises with Loops Fibonacci with loops and new addressing modes: Examples Friday Homework 6 and solution programs	Reading The LOOP Instruction Addressing Modes
Week 7 10/15	Monday A word on the LOOP instruction offset condition codes & status register (flags) Conditional Jumps: JA, JAE, JB, JBE, JC, JCXZ, JE, JG, JGE, JL, JLE, JNA, JNAE, JNB, JNBE, JNC, JNE, JNG, JNGE, JNL, JNLE, JNO, JNP, JNS, JNZ, JO, JP, JPE, JPO, JS, JZ (more info here). Flag bits set by the CMP instruction Wednesday Q&A on midterm exam A comment on RISC and CISC Continuation on conditional jumps Exercises on Conditional Jumps Friday Midterm Preparation Midterm Exam, in class, closed books. Solution No homework assignment this week.	Reading
Week 8 10/22	Monday Using a Makefile Another trick. Keep the nasm, ld, and run commands in one line in your history: nasm -f elf -F stabs myProg.asm ; ld -melf_i386 -o myProg myProg.o ; ./myProg The Shift instructions SHL, SHR, SAR, SAL shl reg, 1 shl mem, 1 shl reg, imm shl mem, imm shl reg, cl shl mem, cl Exercise: print contents of a dword in binary Wednesday Review printing in binary. Run program Difference between shifting and dividing Exercise: Sketch algorithm for printing contents of DWord in hex. Rotate Instructions: ROR, ROL, RCR, RCL Friday Functions and the use of the stack. Exercises on Functions Homework 7 and Solution Programs	Reading Shift Instructions, in the Art of Assembly source. The Call and Ret Instructions Functions and the topics associated with passing parameters are covered in Carter's Manual on Assembly Language, in Chapter 4, titled Subprograms.
Week 9 10/29	Bad!!! Monday No class, thanks to Hurricane Sandy! Wednesday The Magic of Functions Friday Some comments about Homework 7 Top-Down example Homework 8 and solution programs	Reading Functions and the topics associated with passing parameters are covered in Carter's Manual on Assembly Language, in Chapter 4, titled Subprograms.
Week 10 11/05	Move quickly!!! Monday Finish the top-down example Review the actions of passing parameters through registers. The concept of functions returning values is directly implementable using registers (in most cases). Using EBP to pass more than 4/6 dword parameters: int main() { int a=3, b=5, res; res = sum( a, b ); ... } int sum( int x, int y ) { return x+y; } Wednesday review passing of value parameters through the stack functions returning values... Friday Why is this code buggy? local variables... Some ideas for exercises write a function that receives 3 dwords and returns the largest (in eax or in the stack) write a function that receives a number and a char and prints a line with that many copies of it. write a function that copies one array into another one. write a function that receives two arrays: scans first one for patterns and updates second one as it does so. Homework 9 and solution	Reading Functions and the topics associated with passing parameters are covered in Carter's Manual on Assembly Language, in Chapter 4, titled Subprograms.
Week 11 11/12	For Lispers... Monday Events: see info on Interrupts Passing by reference Java passes objects by reference Wednesday Some ideas for exercises write a function that receives 3 dwords and returns the largest (in eax or in the stack) write a function that receives a number and a char and prints a line with that many copies of it. write a function that copies one array into another one. (we discovered a new instruction in the process: movsb) write a function that receives two arrays: scans first one for patterns and updates second one as it does so. write a function (in C, we would write it: swap( int *x, int *y) ) that swaps the values in x and y. A look at the solution programs for Homework 8. Friday Review passing parameters Recursing with Factorials Recursion Homework 10 and solution programs	Reading How the Pentium reacts to interrupts/events
Week 12 11/19	Monday Continuation of recursion. "Walking" the factorial example (see listing) List of Factorials Questions: Any limiting factors? Could we have computed the factorial any other way? Unrolling recursion Sketching the Towers of Hanoi problem in assembly... Wednesday Thanksgiving Break Friday Thanksgiving Break	Reading Section 4.8 in Carter's on recursive programs
Week 13 11/26	Monday Moving disks with the Towers of Hanoi Wednesday Q&A Continuation with the Towers of Hanoi Observe hanoi2.py and its indented output Question 1: how much stack space is used when moving N disks? Question 2: How large a number of disks can we move with a stack of 1000 bytes? Question 3: Removing the tail recursion. How does it affect the stack? Binary Search What does the recursion tree look like for the Binary Search algorithm? Would removing the tail recursion help Binary Search? Printing an integer in decimal. The DIV instruction Sketching a solution A program Limitations of the program? Friday: No Class Homework 11 and Solutions	Reading The DIV instruction is covered in Page 34 of Carter's book]. Recursion is still covered in Section 4.8 of Carter's text.
Week 14 12/03	Monday Reminder: lunch talk by Pippin Wolfe on her research in AI A word about making the Fibonacci program of Homework 10 faster Floating Point Numbers Wednesday Continuing with Floating Point Numbers How to declare a U(8, 8) fixed point number? Exercises with Fixed-Point Notation Adding and multiplying Fixed Points Some important definitions Floating-Point Numbers Friday: No Class Homework 12 and solutions	Reading DT's page on Floating Point Wikipedia's page on the IEEE floating-point format.
Week 15 12/10	Monday More on Floating-Point Numbers Wednesday Last Class Answer to the question: What does the real ligne looks like in terms of how the Floating Point format covers it? Examples of Floating Point programs that generate unexpected results The architecture of the FPU: A stack of 8 80-bit registers: st0, st1, ... st7. Examples of assembly programs using the FPU (also available here) How the FPU performs an addition of two floating point numbers Take-Home Final Exam, open books & computers. Solution	Reading DT's page on Floating Point Wikipedia's page on the IEEE floating-point format. Very good coverage of the unexpected behavior of floating point numbers What every computer scientist should know about FP