Question

1. Write MIPS code for the highlighted part

# Assume that factorial is defined as factorial(int x)
.data

num: .word 8

large_str: .asciiz “Factorial result is large”

small_str: .asciiz
.text
# int y = factorial(num);
lw $t0, num # push this onto the stack before calling factorial(int)
____________
____________
____________
# clean up the stack after wards
____________
# You can use the print string syscall in lieu of a call to printf
# if(y > 200) { printf(large_str); }
addi $t0, $0, 200
bgt $v0, $t0, large
# else { printf(small_str);}
else:
____________

____________
syscall
____________
large:
____________

____________

syscall
end:

li $v0, 10

syscall

Answer 1

PROGRAM:

.data
   num: .word 8
   large_str: .asciiz "Factorial result is large"
   small_str: .asciiz "Factorial result is small"
.text
.globl main
main:
   # int y = factorial(num);
   lw $t0, num
   # push num onto the stack before calling factorial(int)
   addiu $sp,$sp,-4       # Adjusting the stack pointer to store num on the stack
   sw $t0,0($sp)           # Storing num on the stack
   jal factorial           # Calling factorial(num)
   # clean up the stack after wards
   addiu $sp,$sp,4           # Adjusting the stack pointer to its original position
   # You can use the print string syscall in lieu of a call to printf
   # if(y > 200) { printf(large_str); }
   addi $t0, $0, 200
   bgt $v0, $t0, large       # If $v0 is greater than $t0 jump to large
   # else { printf(small_str);}
else:
   li $v0,4           # Call ID to print a string
   la $a0,small_str       # Loading the address of the string to print
   syscall               # call to print the string
   b end               # Branch ti end
large:
   li $v0,4           # Call ID to print a string
   la $a0,large_str       # Loading the address of the string to print
   syscall               # call to print the string
end:
   li $v0, 10           # Call ID to exit the program
   syscall               # Call to exit the program

# Definition of factorial function
factorial:
   addi $sp,$sp,-4       # Adjusting the stack pointer to store return address on the stack
   sw $ra,0($sp)       # Storing return address on to the stack
  
   lw $t0,4($sp)       # Loading number form the stack
   li $t1,1       # Loop variable (i)
   li $t2,1       # Factorial value (fact)
for:   bgt $t1,$t0,return   # If i>num exit
   mul $t2,$t2,$t1       # Else fact = fact * i
   addi $t1,$t1,1       # Increment loop counter (i = i+1)
   b for           # repeat the loop
return:   move $v0,$t2       # Store the value to returned in $v0
   lw $ra,0($sp)       # Loading the return address from stack
   addi $sp,$sp,4       # Adjust stack pointer to its original position
   jr $ra           # Jump back to the calling function
  

Please refer to the following screenshot of the program for indentation of the code:

OUTPUT of the program: