CSC231 Homework 2 2015

--D. Thiebaut (talk) 19:57, 23 September 2015 (EDT)

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This assignment is due on Wed, Sept. 30, 2015, at 11:55 p.m.

Preparation

• ssh to aurora with your 231a-xx account.
• get 3 programs from my 231a account on aurora:

  wget http://cs.smith.edu/~dthiebaut/handout/hw2_1 
  wget http://cs.smith.edu/~dthiebaut/handout/hw2_2
  wget http://cs.smith.edu/~dthiebaut/handout/hw2_3 

• make the programs executable:

  chmod a+rx hw2_*

• you are now ready to work on all 3 problems for this week, which go in increasing levels of complexity.

Problem 1

• Recreate, as exactly as possible, the original program called hw2_1.asm which, when assembled and linked, yielded the program hw2_1.
• Save your program in a file called hw2_1.asm, and make sure that:

• when you assemble and link it (using nasm -f elf, and ld -melf_i386), your executable has the same size as mine, and
• the hexdump of your program matches the hexdump of mine, and, finally,
• the output of your program is the same as the output of mine.

• Submit your program on Moodle, in the HW 2 PB 1 section (when available)

Problem 2

• Recreate, as exactly as possible, the original program called hw2_2.asm which, when assembled and linked, yielded the program hw2_2.
• Save your program in a file called hw2_2.asm, and make sure that:

• when you assemble and link it (using nasm -f elf, and ld -melf_i386), your executable has the same size as mine, and
• the hexdump of your program matches the hexdump of mine, and, finally,
• the output of your program is the same as the output of mine.

• Submit your program on Moodle, in the HW 2 PB 2 section (when available)

Problem 3

• Recreate, as exactly as possible, the original program called hw2_3.asm which, when assembled and linked, yielded the program hw2_3.
• Save your program in a file called hw2_3.asm, and make sure that:

• when you assemble and link it (using nasm -f elf, and ld -melf_i386), your executable has the same size as mine, and
• the hexdump of your program matches the hexdump of mine, and, finally,
• the output of your program is the same as the output of mine.

• Submit your program on Moodle, in the HW 2 PB 3 section (when available)
• Note: I have used some instructions that we haven't see yet (as of 9/23/15), and which are illustrated in the code below:

          mov       eax, ebx         ; copy the contents of ebx into eax
          mov       ebx, eax         ; copy the contents of eax into ebx
          mov       ebx, ecx         ; copy the contents of ecx into ebx
          mov       edx, eax         ; copy the contents of eax into edx
          mov       eax, edx         ; copy the contents of edx into eax