View source for CSC231 Exercises with Mov, Arithmetic and Logic Instructions

--[[User:Thiebaut|D. Thiebaut]] 13:34, 27 September 2010 (UTC)
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=The Mov Instruction=

Assume that we have the following variables declared in the data segment.

<code><pre>


         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    


</pre></code>

;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


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[[Category:CSC231]][[Category:Exercises]]