CSC231 Homework 2 2017

--D. Thiebaut (talk) 16:14, 9 February 2017 (EST)

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This assignment is due on 2/20/17 at 11:55 p.m.

Problem #1

Answer the quizzes in the Moodle Homework 2 section.

Problem #2

In your 231b-xx account on aurora, run the following commands:

getcopy 231Lib.asm
getcopy hw2_skel.asm
cp hw2_skel.asm hw2.asm

You should now have a new file called hw2.asm in your directory, and a library file called 231Lib.asm as well. The library file will help us get input from the keyboard, and print strings.

The hw2.asm file is just a skeleton and you will need to add code to it to solve this problem. For right now, just assemble and link it to the new library, and run it:

nasm -f elf  231Lib.asm
ld -o hw2 hw2.o 231Lib.o
ld -melf_i386 -o hw2 hw2.o 231Lib.o

The program will prompt you for 3 integer numbers, which it will put into three 32-bit integers called a, b, and c in the data segment. It then takes the integer stored in a fourth variable called ans (for answer), and prints it. Since ans is initialized with 0, that's the number that gets printed.

Here's an example of what happens if I run the program and feed it 3 numbers: 1, 2, and 3 (user input underlined):

./hw2
> 1
> 2
> 3
ans = 0