Difference between revisions of "CSC231 Addressing Mode Exercises"
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| − | The example below copies a string into another string, reversing the order of the string to see if | ||
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Latest revision as of 06:22, 2 October 2014
Contents
Exercises on Addressing Modes and Loops
Exercise 1
Indicate the addressing used by each of the instructions below.
;;; ------------------------------------------------------------
;;; Identify possible errors in the instructions below, and
;;; indicate the addressing mode for each one.
;;; ------------------------------------------------------------
section .data
a db 3
b db 0x12345678
c dw 0
x dd 30
array dd 1,2,3,4,5,6,7,8,9,10
section .text
global _start
_start: mov eax, a
mov eax, dword[a] ; is it an error?
mov ebx, array
mov eax, dword[ebx]
mov esi, 0
mov dword[ebx+esi], 0
mov dword[ebx+esi+4], eax
mov edi, b
mov byte[edi], 'Z'
add al, 'z'-'Z'
mov ecx, 10
for: inc ecx
loop for
;;; exit()
mov eax,1
mov ebx,0
int 0x80 ; final system call
Exercise 2
Write a program that changes all the characters of an all-uppercase string to all-lowercase. We assume the string does not contain blank spaces. You can find an ASCII table here.
Exercise 3
Write a program that fills an array of 8 bytes with the first 8 powers of 2: 1, 2, 4, 8, 16, etc.
Exercise 4
Write a program that fills an array of 16 words with the first 16 fibonacci terms
Exercise 5
Write a program that fills an array of 10 double-words with the first 10 powers of 2.
Exercise 6
The example below copies a string into another string, reversing the order of the string (to see if the original string is a palindrome, for example). Rewrite it using a based indexed addressing mode.
