CISC 260汇编语言

CISC 260 Machine Organization and Assembly Language
(Spring 2021)
Assignment # 5
(Due: April 26, 2021)
Problem 1 [15 pts]. Show the IEEE 754 binary representation for the following fraction
numbers in single precision. Give your answer in hexadecimal. State if each number can
be represented exactly.
a. – 18.625
b. 3.14
Problem 2 [15 pts]. What decimal number does the following bit pattern represent if it is
a single precision floating-point number using the IEEE 754 standard?
a. 0xC0210000
b. 0xCD001000
Problem 3 [15 pts]. A single precision IEEE 754 number is stored in memory at address
X. Write a sequence of ARM instructions to multiply the number at X by 16 and store the
result back at X. You must accomplish this without using any floating-point instructions
(you may ignore overflow or underflow). Note: this is a paper-pencil problem.
Problem 4 [15 pts]. At a candy shop, the 1st candy costs 10cents. Each subsequent candy
costs 10 cents more than the previous one. For one dollar, how many candies can you
purchase at most? Here is a program written in C to answer that question.
float fundLeft = 1.0;
float cost;
int numCandies = 0;
for(cost=0.1; cost <= fundLeft; cost += 0.1) {
numCandies++;
fundLeft = fundLeft - cost;
}
printf(”%d candies; %f left over\n”, numCandies, fundLeft);
Run the program and report the result. If the result is not what is expected, explain why?
Modify the program so that the correct answer can be obtained. Present your modified
program.
Problem 5 [40 points]: Implement in ARM7 assembly language a linked list for sorting.
In the main function, open a file to read a sequence of unsorted integers. For the first
input integer, create a root node (8 bytes), holding the integer and one empty pointer. For
each of the following input integers, build a link (call it X) containing the number and
insert it to the linked list such that for any link with smaller integer should go before X
2
and any link with an integer of bigger or equal value should go after X. After all integers
are inserted, the program would traverse the linked list and print out the sorted integers
separated by space onto the screen. (See next page)
Specification: you should write Insert as a recursive function.
Submission: For problem 5, a plain text file (with .s extension) containing your
assembly code should be submitted on Canvas.
data Null or a Pointer to
the next node