Description
Problem 1: GNU Debugger (GDB) (5 pt)
Please write the command(s) you should use to achieve the following tasks in GDB.
1. Show the value of variable “solution” in hex format.
2. Show the top four bytes on your stack word-by-word. It should look something like this “0x0102
0x0304”, NOT “0x01020304”.
3. Print all register values.
4. Set a breakpoint at “ece.c” line 391.
5. Connect to the test_(no)debug vm in the lab setup.
Please write your solution in p1_soln.txt with answers to each question on a separate line, separated by blank
lines. For example, your p1_soln.txt should be of the form
answer 1
answer 2
…
answer 5
Problem 2: C to Assembly Translation (10 pt)
Problem Set 1 ECE391 2 / 3
Write x86 assembly code for the body of the edit_dist function found in edit_dist.c. Make sure to set up
and tear down the stack frame as well as save and restore any callee/caller-saved registers yourself (if you use
them). Include comments (but don’t overdo it!) in your assembly code to show the correspondence between
the C code and your x86 code.
Also note that:
1. The edit_dist_asm function in edit_dist_asm.S is partially filled out for you, your job is to complete
the function.
2. Please make sure that your code and comments are easy to read. We reserve the right to take points off
if your answer is too hard to follow.
3. You must synthesize your answer without the help of a computer. For example, you may not write the C
code and then use the compiler to disassemble it. If you are caught doing this, you will receive a 0.
4. There need not be a one-to-one mapping between the C and Assembly codes, but you have to
translate using the exact same algorithm (in other words, if the provided function uses a recursive
method, you cannot translate using a dynamic programming method). If you fail to use the approach
taken in the C code, you will receive a 0.
5. You must write your solution in p2/edit_dist_asm.S and submit it through gitlab.
Problem Constraints:
You can assume that all input txt files are valid (in other words, only numbers, no letters, no overflow)
You can assume that all numbers in the linked list are non-negative integers.
To build the code (no debug flag): $ make clean && make
To run the code: $ ./edit_dist ./1_list.txt ./2_list.txt
To build the code (debug flag): $ make clean && make debug
To run the code (debug): $ gdb –args ./edit_dist ./1_list.txt ./2_list.txt
Problem 3: Assembly to C Translation (10 pt)
Write a C function equivalent to the x86 assembly function, mystery_asm found in mystery_asm.S.
1. Please make sure your code and comments are easy to read. We reserve the right to take points off if
your answer is too hard to follow.
2. There need not be a one-to-one mapping between the C and Assembly codes, but you must translate
your code. A functionally equivalent algorithm with a different structure will receive no credit. (For
example, if the provided function uses a recursive method, you cannot translate using an iterative
method)
3. You must write your solution in p3/mystery.c and submit it through gitlab.
Problem Constraints:
Problem Set 1 ECE391 3 / 3
You can assume that x and y are non-negative integers.
You don’t need to worry about overflow situations.
To build the code (no debug flag): $ make clean && make
To run the code: $ ./mystery ./1_input.txt
To build the code (debug flag): $ make clean && make debug
To run the code (debug): $ gdb –args ./mystery ./1_input.txt
