4. (20 points) Manipulate the program assembly code so that it it implements and prints out the return value of this function:

int nested_loop_test(int n){

int rv = 1;

for(int i = 1; i < n;i*=2)

for(int j = i; j >=0; j--)

if(j % 2 == 0)

rv += (i + j);

else

rv += (2*i-3*j);

return rv;

}

Here is the Program to Manipulate:

.text main: # Prompt user to input non-negative number la $a0,prompt li $v0,4 syscall li $v0,5 #Read the number(n) syscall move $t2,$v0 # n to $t2 # Call function to get cube_sum #n move $a0,$t2 move $v0,$t2 jal cube_sum #call cube_sum (n) move $t3,$v0 #result is in $t3 # Output message and n la $a0,result #Print C_ li $v0,4 syscall move $a0,$t2 #Print n li $v0,1 syscall la $a0,result2 #Print = li $v0,4 syscall move $a0,$t3 #Print the answer li $v0,1 syscall la $a0,endl #Print ' ' li $v0,4 syscall # End program li $v0,10 syscall #int cube_sum(int n){int sum = 0; #for(int i = 0; i <= n;i++)sum+=cube(i); #return sum;} cube_sum: # Compute and return cube_sum number #Push $ra $s0, and $s1 to stack addi $sp,$sp,-16 sw $ra,0($sp) #storing return address in stack sw $s0,4($sp) #storing first saved register in stack sw $s1,8($sp) #storing second saved register in stack sw $s2,12($sp) #storing third saved register in stack move $s0, $a0 #n is now stored in $s0 move $s2, $zero #sum is now stored in $s2 and initialized to zero addi $s1, $zero, 1 #i is stored in $s1 and initialized to 1 for: slt $t0, $s0, $s1 bne $t0, $zero, exit #body of for loop move $a0, $s1 jal cube add $s2, $s2, $v0 #sum += cube(i) #end of for loop addi $s1, $s1, 1 j for exit: move $v0, $s2 #returning sum lw $ra,0($sp) #restoring return address from stack lw $s0,4($sp) #restoring first saved register from stack lw $s1,8($sp) #restoring second saved register from stack lw $s2,12($sp) #restoring third saved register from stack addi $sp,$sp,16 jr $ra #int cube(int n){ # return n*n*n; #} cube: #compute the cube of a number mul $t0, $a0, $a0 mul $t0, $t0, $a0 move $v0, $t0 jr $ra .data prompt: .asciiz "This program calculates the sum of cube sequence. Enter a non-negative number less than 100: " result: .asciiz "C_" result2: .asciiz " = " endl: .asciiz " "