CSC231 Class Page 2015

--D. Thiebaut (talk) 11:28, 26 August 2015 (EDT)

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Main Page | Syllabus | Weekly Schedule | Links & Resources |Piazza

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Week 1 Sept 7

Topics: Introduction, Python, Idle, Piazza, Moodle submission	Lab/Hw	Reading
Wednesday 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	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. Note, Carter uses 1A92h to represent a hexadecimal number. I prefer 0x1A92.

 

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Week 2 Sept. 14

Topics: Processor and Memory, working with the shell, and emacs.	Lab/Hw	Reading
Monday: Review PC destruction lab. Main players: Processor, cores, RAM, motherboard, crystal How would Richard Tuttle see a computer motherboard? This is some of his artwork. First diagram of a computer as seen by an assembly language programmer Review Hello World program with this new knowledge Notice how the main character uses all kinds of software packages to solve his problem. It includes working in a shell, using shell commands, and mixing the results with various programming techniques. Wednesday Linux System Calls. See Slide 5 of this presentation Working in a shell The bash shell Playing with the shell using 231a-xx accounts Useful commands ls, cd, pwd, mkdir, rm, rmdir, cp history, !, !!, alias, w, ps, who am i grep, wc, head, tail Redirection Pipes Emacs quick overview (see this page) set of commands Lab 1, Part 1: Shell commands: go to this page Lab 1, Part 2: Emacs: go to this page	Lab Homework

 

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Week 3 Sept. 21

Topics: Number Systems, the MOV instruction	Lab/Hw	Reading
Monday: Let's talk about the crystal Relationship with instructions Power-law for increase in processor speed Ray Kurzweil on Power Laws (go to marker 3:30 min in video) Playing a game of numbers Hexadecimal system: for i in range( 256 ): print( i, format( i, '02X' ) ) Assembly: Review nasm, ld Understanding how data fits in memory: printing strings defined by db Size of a program: data + code size helloWorld2 text data bss dec hex filename 34 14 0 48 30 helloWorld2 Listing of the assembly and its code: nasm -f elf -l helloWorld2.lst helloWorld2.asm ls ... helloWorld2.lst ... Ascii Table Wednesday Quick check of number conversion skills Observe output of nasm -l (helloWorld2.lst) Another way to look at the executable file with hexdump hexdump -v -C helloWorld2 00000000 7f 45 4c 46 01 01 01 00 ... ... 000002b0 74 61 00 5f 65 6e 64 00 |ta._end.| 000002b8 Observe the output of hexdump command Snooping around the code of an executable Lab #2 The Mov instruction	Lab #2 Homework #2 and Solution programs (at end of page)	Finish the reading assigned for Week 1. The mov instruction

 

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Week 4 Sept. 28

Topics: The Mov instruction. Arithmetic instructions. Addressing Modes.	Lab/Hw	Reading
Monday: The MOV instruction, and examples of mov instructions Wednesday A script to automatically assemble and link assembly programs Review: MOV instruction: direct and immediate modes of addressing data Examples: copying a string to another string Exercises with the MOV instruction The ADD instruction Overly-simplified encryption of a string	Mini Lab 3 Homework 3 and Solutions (at end of page)	Chapter 3, Section 1 in The Art of Assembly, to Section 3.2.2.

 

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Week 5 Oct 5

Topics:	Lab/Hw	Reading
Monday: Arithmetic instructions: ADD, SUB, INC, DEC. Skip MUL and DIV for right now. A quick introduction to calling functions: CALL and RET Printing decimal numbers in assembly A first look at what is behind code like this: int a; int b; int c; a = 3; b = 5; c = a + b; Example of what the GNU cc compiler would have generated Exercise 1: "Compile" the following statements to assembly: int a; int b; int c; int d; a = 3; b = 5; c = a*2 + b; d = (a + b + 10 + 2*c ) * 2 - 20; Exercise 2: translate the following code in assembly. If you need to refresh your memory on Java types, check this document out: int a = 3, b = 5, c; short d = 10, e = 0xff, f = 0; c = ( a * 2 + b ) * 3; f = d + (e-1); c = a * 2* d; Wednesday Mountain Day?		Big Endian vs. Little Endian hardware. Why does it matter? page with some little-endian and big-endian architectures. Section 4.1 of Paul Carter's ebook presents indirect addressing. Read this first. Read also Section 5.1.3 about more sophisticated indirect addressing modes. The CALL and RET instructions

 

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Week 6 Oct. 12

Topics: call/ret, looping, mul/div	Lab/Hw	Reading
Monday: Fall Break Wednesday Back to call and ret instructions: defining and using functions. Exercise 1: Create a function that adds two int variables together Exercise 2: Add a function that prints the two variables and their sum mul and div: multi-register instructions. EDX:EAX used as default registers. Exercise 3: Write a Teller-Machine program The loop instruction: ECX is the counter Program 1: function computes sum of 2 ints Program 2: compute sum of 2 ints and print sum	Homework #4	LOOP: Read Section 2.2.3 (Page 41) in Paul Carter's book. MUL: Read Section 2.1.3 (Page 33) in Paul Carter's book. Do not worry about the mention of 2's complement. Just concentrate on the registers that are used. CALL/RET: Section 4.4 (Page 65) in Paul Carter's book.

 

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Week 7 Oct 19

Topics:	Lab/Hw	Reading
Monday: Back to mul and div: Java and Python multiply ints differently Exercise 1: Write a Teller-Machine program The loop instruction: ECX is the counter Exercise 2: Compute the sum of all ints between 1 and n. (There are many possible answers) Exercise 4: What is the largest amount of looping we can do with the loop instructions? Exercise 5: How long does it take a loop to accumulate the sum of all the ints between 1 and 1,000,000? Any particular issues one should be worried about? Program 3: Teller machine program. Program 4: Teller machine with function. Wednesday Comparing execution speed of Java vs C++, vs Nasm, vs Python. Measuring user time with the Linux time command: The user time is how long your program was running on the processor. The sys time is how long your program was waiting for the OS to perform tasks for it. In general, (user time + sys time) is a good approximation of the time your program needs to run to completion. The real time contains the time that other processes took out of the CPU while your program was running. How many processes are running at the same time? ps and top commands. Addressing modes: the response of processor designers to the complexity of high-level languages. Slides on addressing modes inherent register immediate direct indirect/based/indexed indirect with displacement base-indexed base-indexed with displacement Exercises on Loops Exercises on Loops and Addressing Modes (Problems 2 to 6)	No homework this week. Prepare for the midterm!	Section 4.1 of Paul Carter's ebook presents indirect addressing. Read this first. Read also Section 5.1.3 about more sophisticated indirect addressing modes.

 

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Week 8 Oct. 26

Topics:	Lab/Hw	Reading
Monday: Midterm Exam: in class, on paper, closed everything. Midterm Preparation Wednesday Logic Instructions: OR, AND, XOR, NOT: they work in binary! Using logic instruction to mask various bit sections. Exercise: Clear the upper 16 bits of eax Set the upper 4 bits of al to 0 Set the lower 4 bits of al to 1 Print AL in hex. Logic Gates: AND, OR, and NOT. That's what a computer is made of! Taking a look at the mother board of an Apple computer. The AND, OR, and Inverter gates in one pdf Schematics from NASA, and a specific sheet showing logic gates. Schematics of 2-bit Adder AND, OR, (XOR), NOT (on [Wikipedia])	Homework 5	Reading Logical Operations on Bits 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.

 

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Week 9 Nov. 2

Topics: And, Or, and Not gates. Signed Integer format.	Lab/Hw	Reading
Monday: The AND, OR, and Inverter gates in one pdf Schematics from NASA, and a specific sheet showing logic gates. Schematics of 2-bit Adder AND, OR, (XOR), NOT (on [Wikipedia]) A 2-bit adder with logic gates. Slides on Number Systems (updated) Example in C++ (Java does not support unsigned ints!) // signedUnsigned.cpp // compile and run: // g++ signedUnsigned.cpp // ./a.out // #include <iostream> #include <stdio.h> using namespace std; int main( int argc, char *argv[] ) { unsigned u = 1; // unsigned int variable int i = 1; // signed int while ( 1 ) { // forever i = i*3; u = u*3; cout << " u = " << u << endl; cout << " i = " << i <<endl; getchar(); // wait for user to press ENTER } } Exercises Wednesday Continue with Exercises on signed number representation The range of unsigned and signed ints, as byte, words, double words, 64-bit words. See this Microsoft page on C++ for actual ranges The NEG and NOT instructions. What is the 32-bit equivalent of a 16-bit 2's complement number? What is the rule for extending numbers in 2's complement? The CWDE instruction Mystery problem of the day... In case we need it: 4-bit chart Where does the carry bit go, when an add eax, value is performed? Introduce the FLAGS register The CMP instruction: Compare: a SUB instruction that does not store the result anywhere! 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). Examples of how flag bits are set	Homework 6	Signed and unsigned numbers are covered in Sections 1.7 and 1.8 and Chap. 2 The NEG instruction The CWDE instruction The [CMP instruction

 

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Week 10 Nov 9

Topics: Conditional Jumps, Push & Pop	Lab/Hw	Reading
Monday: Unconditional Jump: JMP Review ALU, Flag bits, Instructions that set flag bits. CMP is a SUB that does not store the result of the subtraction. Typical compare/jump instructions: cmp op1, op2 jne notEqual ... jmp done notEqual: ... done: ... Examples of instructions that affect the flag bits Exercises to put all this into place Wednesday Video lecture. Information about the current homework is given at the end of the video.	Homework 7	The CMP instruction The conditional jumps page in Randy Hall's Art of Assembly. Push and Pop instructions.

 

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Week 11 Nov 16

Topics:	Lab/Hw	Reading
Monday: Review Push/Pop Passing Parameters ( Lecture slides (pdf)) Passing Parameters via registers (and bits) Passing parameters via the stack: we need a new register: EBP! Passing by value Passing by reference Function returning values sumProc1.asm: Pass through registers sumProc2.asm: Pass by value sumProc3.asm: Int returning function sumProc4.asm: Pass by reference Wednesday sumProc5.asm: Local variables Tips, tricks, and no-nos.	No new homework this week. Homework 7 extended.	Procedures and Functions. They are basically the same. Procedure is often used to refer to a function that does not return anything. Push and Pop instructions. Call and Ret instruction. Functions and the topics associated with passing parameters are covered in Carter's Manual on Assembly Language, in Chapter 4, titled Subprograms.

 

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Week 12 Nov 23

Topics:	Lab/Hw	Reading
Monday: Review passing parameters, by value, by reference, functions returning values, and local variables. Review stack frame. Writing the recursive function for the Factorial problem. Wednesday: Thankgiving Break

 

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Week 13 Nov 30

Topics:	Lab/Hw	Reading
Monday: A note on benchmarking... Tips and Tricks Recursion: A Python simulator for Factorial.asm Wednesday Exercises How much stack space is required for computing the factorial of 1000? What else, besides the stack, should we be worried about? How much stack space, at least, and at most, would we need to recursively visit a 1000x1000 maze? You can find a Java maze traversing program here. Express your answer in KB, MB, or GB. Stack Overflow in Java Floating-Point Numbers Slides for Fixed-Point & Floating-Point formats	Homework 8	Introduction to Fixed- and Floating-Point Numbers

 

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Week 14 Dec 7

Topics:	Lab/Hw	Reading
Monday: Floating Points Wednesday Floating Points

 

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Week 15 Dec 14

Topics:	Lab/Hw	Reading
Monday: Last Class: Presentation of the take-home final exam. The exam will be due at 4:00 p.m. on the last day of exams.	Final Exam

Links and Resources

• Notes on Assembling 32-bit Code on 64-bit Machines
• Hello Word in assembly running on Mac OS and on Linux