#  Check for leap year (draw the flowchart)
#  In Gregorian Calendar: "A year is a leap year if it is divisible by 4 with
#           the exception of century years that are not divisible by 400"
#  That is: if (Year mod 4 <> 0) then Ordinary
#           else if (Year mod 100 = 0) and (Year mod 400 <> 0) then Ordinary
#           else Leap

         .text
         .globl __start

__start: li $v0, 4
         la $a0, Prompt
         syscall                # Print a prompt

         li $v0, 5
         syscall                # Read an integer
         sw $v0, Year           # and store it in Year

#  if (Year mod 4 <> 0) then go to Ordinary

         lw $t0, Year
         li $t1, 4
         div $t0, $t1            # hi = year mod 4 
         mfhi $t1                # $t1 = hi
         bne $t1, $0, Ordinary   # if $t1 <> 0 go to Ordinary

# if (Year mod 100 = 0) and (year mod 400 <> 0) then go to Ordinary

# if (Year mod 100 <> 0) then go to Leap

        li $t1, 100
        div $t0, $t1             # hi = year mod 100 
        mfhi $t1                 # $t1 = hi
        bne $t1, $0, Leap        # if $t1 <> 0 go to Leap

# if (Year mod 400 <> 0) then go to Ordinary

          li $t1, 400
          div $t0, $t1           # hi = year mod 400 
          mfhi $t1               # $t1 = hi
          bne $t1, $0, Ordinary  # if $t1 <> 0 go to Ordinary

Leap:     lw $a0, Year           # Leap year
          li $v0, 1
          syscall                # Print Year
          li $v0, 4
          la $a0, LeapMess
          syscall                # Print " is a leap year\n"
          b End                  # go to End

Ordinary: lw $a0, Year           # Ordinary year
          li $v0, 1
          syscall                # Print Year
          li $v0, 4
          la $a0, OrdMess
          syscall                # Print " is an ordinary year\n"

End:      b __start              # go to __start (read another year)
 
          .data
Year:     .word 0
Prompt:   .asciiz "Enter year: "
LeapMess: .asciiz " is a leap year\n"
OrdMess:  .asciiz " is an ordinary year\n"