Triangles.asm

# Author:   Madeline Chubb  +  Jacob Gallucci
# E-mail:   mac6920@psu.edu   + jag6248@psu.edu
# Course:   CMPSC 312
# Assignment:   MIPS Programming Project
# Due Date: 4/11/2018
# File: TriangleWithLoop.asm
# Purpose:  This program prompts a user to enter 3 positive integers and reports whether or not they form a triangle.
# Simulator:    Mars 4.5
# Operating
# System:   macOS High Sierra 10.13.2 (Maddie)  + Debian 9 Stretch (Jacob)  + Windows 8.1 (Jacob)
#               (SO basically this should work on literally any operating system... *BSD untested but we're sure it works
#    References:    Class demo programs
#       https://www.youtube.com/watch?v=B0GAXDjfdbQ (How to get user input)
#       http://forums.devshed.com/programming-languages-139/mips-finding-largest-integers-3-inputs-858246.html
#       (How to compare integers)

.data  # Output Variables

# Prompt user for input
prompt:     .asciiz "Enter 3 positive integers by pressing <enter> after each: "

# New Line
newline:    .asciiz "\n"

# Invalid Input Response
error:      .asciiz "Invalid Input!\n"

# Separator Line
format:     .asciiz "*************************************************************************\n"

# Prompt user to input another triangle
continue:   .asciiz "Do you want to test more integers? (Type 0 to quit, 1 to run again.): "

# Lengths do not form a triangle
nope:       .asciiz "These integers do NOT form a triangle.\n"

# Lengths do form a triangle
yes:        .asciiz "These integere DO form a triangle.\n"

.text # Section containing code
.globl main # Execution start point

main:
        li $v0, 4      # Loads string to print (4)
        la $a0, prompt # Prints String
        syscall        # Executes above code

        li $v0, 4           # Loads string to print (4)
        la $a0, newline     # Prints string new line
        syscall             # Executes above code

        li $v0, 5           # Gets user integer input (5)
        syscall             # Executes above code

        move $t0, $v0       # Stores v0 register in t0
        blez $t0, invalid   # If t0 is less than or equal to 0 Goes to label invalid for user to input another integer
        li $v0, 5           # Gets user input (5)
        syscall             # Executes above code

        move $t1, $v0       # Stores v0 in t1
        blez $t1, invalid   # If t1 is less than or equal to 0 Goes to label invalid for user to input another integer
        li $v0, 5           # Gets user input (5)
        syscall             # Executes above code

        move $t2, $v0       # Stores v0 in t2
        blez $t2, invalid   # If t2 is less than or equal to 0 Goes to label invalid for user to input another integer

        li $v0, 4           # Loads string to print (4)
        la $a0, newline     # Prints string new line
        syscall             # Executes above code

        add $t3, $t0, $t1   # Adds t0 and t1 and stores in t3
        bge $t2, $t3, notTri    # if t3 is bigger than t2, go to label not triangle (notTri)
        add $t4, $t0, $t2   # Adds t0 and t2 and stores in t4
        bge $t1, $t4, notTri    # if t4 is bigger than t1, go to label not triangle (notTri)
        add $t5, $t1, $t2   # Adds t1 and t2 and stores in t5
        bge $t0, $t5, notTri    # if t0 is bigger than t5, go to label not triangle (notTri)

        b yesTri # if passes all above tests go to yes it is a triangle (yesTri)

# invalid label
invalid:
        li $v0, 4     # Loads string to print (4)
        la $a0, error # Prints error string (invalid input)
        syscall       # Executes above code
        b main        # Goes back to main label

# notTriangle label
notTri:
        li $v0, 4     # Loads string to print (4)
        la $a0, nope  # Prints not a triangle string
        syscall       # Executes above code
        b loop        # Goes to loop label (to ask user if they wish to go again)

# yesTri label (if inputted lengths are a triangle)
yesTri:
        li $v0, 4    # Loads string to print (4)
        la $a0, yes  # Prints string (yes it is a triangle)
        syscall      # Executes above code
        b loop       # Goes to loop label (to ask user if they wish to go again)

# Loop label (prompts user to go again)
loop:
        li $v0, 4       # Loads string to print (4)
        la $a0, format  # Prints string (divider line)
        syscall         # Executes above cude

        li $v0, 4        # Loads string to print (4)
        la $a0, continue # Prints string (prompts user to choose to go again)
        syscall          # Executes above code

        li $v0, 5        # Gets user integer input (5)
        syscall          # Executes above code
        move $t7, $v0    # stores v0 in t7

        li $v0, 4        # Loads string to print
        la $a0, format   # Prints string (divider line)
        syscall          # Executes above code

        blez $t7, end       # if input is less than or equal to 0 , goes to end label (to end the program)
        bge $t7, 1, main    # if input is greater or equal to 1, goes to main label (loops again - go again)

# End label (ends program)
end:
        li $v0, 10     # Loads exit program
        syscall        # Executes above code (and ends)