CSE 2312 - Assignments

Not Graded Practice for Assignment 7

Practice Question 1

(This is Problem 25 from Chapter 5 of the textbook).

Compute the Boolean bitwise expression (A AND B) OR C for:

        A = 1101 0000 1010 0011
        B = 1111 1111 0000 1111
        C = 0000 0000 0010 0000

AND and OR must be performed in a bitwise manner.

Practice Question 2

(This is Problem 26 from Chapter 5 of the textbook).

Devise a way to interchange two variables A and B without using a third variable or register. Hint: Think about the EXCLUSIVE OR instruction.

Practice Question 3

(This is Problem 27 from Chapter 5 of the textbook).

On a certain computer it is possible to move a number from one register to another, shift each of them left by different amounts, and add the results in less time than a multiplication takes. Under what condition is this instruction sequence useful for computing "constant * variable"?

Practice Question 4

For the previous question (textbook problem 5.27), would that instruction sequence be equally useful for computing "variable * variable"? Justify your answer.

Practice Question 5

Write assembly code that:

Compares r1 with r2.
If the contents of r1 are smaller than the contents of r2, print r1 (that is, just the string "r2").
If the contents of r2 are smaller than the contents of r1, print r2 (that is, just the string "r2").
If the contents of the two registers are equal, print an equal sign (that is, just print "=").

For example, when your code is placed at the indicated position, the program below should print "r1".

.globl _start
_start:
        mov r1, #15
        mov r2, #20

        @@@ Place your code here.

Practice Question 6

Write assembly code that: assuming that r1 holds a value between 0 and 19, prints out that value in decimal. If r1 holds a value less than 0 or greater than 19, your program should print "no". For example, when your code is placed at the indicated position, the program below should print 17.

.globl _start
_start:
        mov r1, #17

        @@@ Place your code here.

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