# merge sort

      .text
      .globl  main
main:
      la		$a0, array1
      la		$a1, array2
      la		$a3, array3
      jal	merge

# store the amount of elements to be printed
      add	$t0, $0, $0
      add	$t1, $0, $v0
      sll	$t1, $t1, 2

#print the number of elements first      
      add	$a0, $v0, $0
      li		$v0, 1
      syscall
      
#print the elements of the array
loop2:
      li		$v0, 4	
      la		$a0, str
      syscall
      lw		$a0, array3($t0)
      li		$v0, 1
      syscall
      add	$t0, $t0, 4
      bne	$t0, $t1 loop2
      j		finish
      
      
## merge function
merge:
      add	$t0, $a0, 0		# t0 indexes array1
      add	$t1, $a1, 0		# t1 indexes array2
      add	$t2, $a3, 0		# t2 indexes array3
      
      lw		$t3, ($t0)		# the amount of ints in array
      lw		$t4, ($t1)
      
      add	$v0, $t3, $t4		# the value to be returned
      
      add	$t0, $t0, 4		# point to the real start of
      add	$t1, $t1, 4		# both arrays
      
      sll	$t3, $t3, 2		# the amount of bytes in array
      sll	$t4, $t4, 2		# 
      
      add	$t3, $t0, $t3		# the final location in array
      add	$t4, $t1, $t4		# jw:	 these now point past the last element

      
      
loop:
      lw		$t5, ($t0)		# load the values from the arrays
      lw		$t6, ($t1)		#
      slt	$t7, $t5, $t6		#
      bne	$t7, 1 else		# if (t5<t6)
      sw		$t5, ($t2)		# store t5 in array3
      add	$t0, $t0, 4		# increment array1 index
      j		endif			
else:					# else
      sw		$t6, ($t2)		# store t6 in array3
      add	$t1, $t1, 4		# increment array2 index
endif:					# endif
      add	$t2, $t2, 4		# increment array3 index
      beq	$t0, $t3 endloop1	# break if t0 is at the end
      beq	$t1, $t4 endloop2	# break if t1 is at the end
      j		loop
      
# now finish off the end of the array we didn't use up

endloop2:
      lw		$t5, ($t0)
      sw		$t5, ($t2)
      add	$t0, $t0, 4
      add	$t2, $t2, 4
      bne	$t0, $t3 endloop2
      jr		$ra
      
endloop1:
      lw		$t5, ($t1)
      sw		$t5, ($t2)
      add	$t1, $t1, 4
      add	$t2, $t2, 4
      bne	$t1, $t4 endloop1
      jr		$ra	
   
finish:
      
      .data
      .align  2  # make sure that the array starts at an address that is a multiple of 4
array1:
      .word 5,3,5,7,9,10

array2:
      .word 5,2,3,3,4,12
      
array3:
      .word 0,0,0,0,0,0,0,0,0,0
      
str:
      .asciiz " "