I am trying to implement a MIPS calculator that takes 3 ints as input and returns an output. Currently, the code outputs "The sum of int1, int2, and int3 is 1" and I don't understand why. Perhaps I haven't written the addition subroutine properly?
.data
welc: .asciiz "Enter an integer:\n"
sum: .asciiz "The sum of "
prod: .asciiz "The product of "
divi: .asciiz "The quotient of "
subt: .asciiz "The difference of "
also: .asciiz " and "
comma: .asciiz ", "
rem: .asciiz "remainder:"
is: .asciiz " is "
int1: .word 1 #space to hold first int
int2: .word 1 #space to hold second int
int3: .word 1 #space to hold third int
input: .space 1 #space to hold raw input
out: .word 1 #space to hold output
remain: .word 1 #space to hold remainder
.text
.globl main
main : li $v0, 4 #syscall 4, print string
la $a0, welc #give argument: string "Enter an integer:"
syscall
li $v0, 5 #tell syscall we want to read int 1
syscall
la $s1, int1 #load int1 into $s1
sw $v0, 0($s1) #copy int from $v0 to int 1
li $v0, 4 #syscall 4, print string
la $a0, welc #give argument: string "Enter an integer:"
syscall
li $v0, 5 #tell syscall we want to read int 2
syscall
la $s2, int2 #load int2 into $s2
sw $v0, 0($s2) #copy int from $v0 to int 2
li $v0, 4 #syscall 4, print string
la $a0, welc #give argument: string "Enter an integer:"
syscall
li $v0, 5 #tell syscall we want to read int 3
syscall
la $s3, int3 #load int3 into $s3
sw $v0, 0($s3) #copy int from $v0 to int 3
la $s0, out #load output to $s0
j plus #jump to calc
plus: add $s0, $s1, $s2 #add int1 and int2 and put in out
add $s0, $s0, $s3 #add out and int3
li $v0, 4 #tell syscall to print string
la,$a0, sum #print sum string
syscall
li $v0, 1 #tell syscall to print int
la $s1, int1 #tell syscall to print int1
lw $a0, 0($s1) #load int 1 into $a0 and print
syscall
li $v0, 4 #tell syscall to print string
la,$a0, comma #tell syscall to print comma
syscall
li $v0, 1 #tell syscall to print int
la $s2, int2 #tell syscall to print int2
lw $a0, 0($s2) #load int 2 into $a0 and print
syscall
li $v0, 4 #tell syscall to print string
la,$a0, comma #tell syscall to print comma
syscall
li $v0, 4 #tell syscall to print string
la,$a0, also #tell syscall to print comma
syscall
li $v0, 1 #tell syscall to print int
la $s3, int3 #tell syscall to print int3
lw $a0, 0($s3) #load int 3 into $a0 and print
syscall
li $v0, 4 #tell syscall to print string
la,$a0, is #tell syscall to print is
syscall
li $v0, 1 #tell syscall to print int
la $s0, out #tell syscall to print output
lw $a0, 0($s0)
syscall
li $v0, 10 #exit code
syscall
In $s0, $s1, and $s2 you have addresses. Therefore in $s0 you have the sum of addresses which is not want you want. Also, you're outputting the value at out, which you never changed.
Before you add the numbers, you must load their value with lw. Then, if you want to print the value at out, you have to store $s0 at that address first.