Using the MARS or SPIM simulator develop a program that will

Using the MARS or SPIM simulator develop a program that will evaluate the following expression: 3 * n + n * (n - 1) - 15 where n is stored in a data location and is set to 15. Your program should use the system calls to print the result and to exit the program. Using the MARS or SPIM simulator develop a program that will implement the following conditional statement. If (n is even) {n = n/2;} else {n = 3 * n + 1; In this case, n is to be input by the user (assume they input a non-negative value), the conditional is performed, and the resulting n is to be output. Again, use the system calls for input, output, and exiting the program.

Solution

Section 1) MARS program

# MARS program to evaluate the mathematical expression 3*n+n*(n-1)-15
.data # variable declarations
n:.word 15 # create a integer variable with initial value 15
.text # instructions
lw $s1,n # load n to destination register.
li $s2,3 # load register $s2 with 3
mult $s1,$s2 # Perform multiplication 3*n
mflo $s4 # moving result saved in lo to $s4
addi $s5,$s1,-1 # evaluating 15-1 by $s5 = $s1-1
mult $s1,$s5 # Performing multiplication n*(n-1)
mflo $s5 # moving result saved in lo to $s5
addi $s6,$s5,-15 # Performing n*(n-1)-15 and result in $s6
add $s7,$s6,$s4 # add $s6 and $s4 for 3*n+n*(n-1)-15
li $v0, 1 # load print system call code into register $v0;
move $a0,$s7 # moving the result to $a0 to print
syscall # system call to print the result
li $v0,10 # load exit system call code into register $v0;
syscall # system call to exit

Result

240
-- program is finished running --

Section 2) MARS program

.data
# instruction to the user to enter the number n
    n: .asciiz \"enter the value of n: \"
.text
    la $a0, n # string to print
    li $v0, 4 # print string
    syscall # system call to print strin in n
    li $v0, 5 # integer input
    syscall # system call for input
    move $s0, $v0 # copy input to s0
    andi $s1, $s0, 1 #bitwise and immediately to know even or not
    beq $s1, $zero, even # even number
    li $s2,3 # load register $s2 with 3
    mult $s0,$s2 # Perform multiplication 3*n
    mflo $s4 # moving result saved in lo to $s4
    addi $s5,$s4,1 # evaluating 3*n+1
    j done # jump to done
even:
    li $s4, 2
    div $s5, $s0, $s4 # devision by 2
    j done
done:   
    li $v0, 1 # load print system call code into register $v0;
    move $a0,$s5 # moving the result to $a0 to print
    syscall # system call to print the result
    li $v0,10 # load exit system call code into register $v0;
    syscall # system call to exit

Result

enter the value of n: 6
3
-- program is finished running --

enter the value of n: 5
16
-- program is finished running --