CSC231 Exercises with Mov, Arithmetic and Logic Instructions
--D. Thiebaut 13:34, 27 September 2010 (UTC)
The Mov Instruction
Assume that we have the following variables declared in the data segment.
section .data
msg1 db "hello world", 10
MSGLEN equ $-msg1
msg2 db " "
msg3 db " "
msg4 db "A man, a plan, a canal, Panama"
MSG3LEN equ $-msg4
msg5 db " "
fib1 db 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233
FIB1LEN equ $-fib1
fib2 db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
fib3 dw 1, 1, 2, 3, 5, 8, 13
FIB3LEN equ ($-fib3)/2
fib4 dw 0, 0, 0, 0, 0 ,0, 0
fib5 dd 1, 1, 2, 3, 5, 8, 13, 23
fib6 dd 0, 0, 0, 0, 0, 0, 0, 0
- Question 1
- Write the instructions necessary to move the contents of msg1 into msg2. Remember: we do not know loops yet, so don't try to use loops.
- Question 2
- Same as Question 1, but into msg3, and this time with as few instructions as possible.
- Question 3
- msg4 is a palyndrome. Reverse it into msg5 with MOV instructions.
- Question 4
- Copy the array fib1 into fib2 with MOV instructions.
- Question 5
- if the array fib1 were one byte longer, what would that byte contain, assuming that it represents the next fibonacci term of the series?
- Question 6
- Copy fib3 into fib4
- Question 7
- Copy fib5 into fib6
Arithmetic Instructions
These questions assume that you know how to use ADD, INC, SUB, DEC, AND, OR, XOR.
- Question 1
- Assume that the array fib4 contains all 0s, as shown above, write the instructions necessary to compute the fibonacci terms and store the first 7 terms into it.
- Question 2
- Assume that we want to increment all the bytes of fib1 by 1. Figure out as many different solutions for this problem.
- Question 3
- what are the contents of eax and ebx at the end of the following group of instructions:
mov eax, 0xff
mov ebx, 5
xor eax, ebx
xor ebx, eax
xor eax, ebx
