linkedList

	.data
fnf:	.ascii  "The file was not found: "
arrow: 	.asciiz "->"
msg:	.asciiz "\nThe very last value in the linked list is: "
eol:	.asciiz "\nThe end of the list was found at position "
file:	.asciiz	"Part3Input.txt"
fout:	.asciiz "Part3Output.txt"
cont:	.ascii  "File contents: "
LB:	.asciiz "\n"
buffer: .space 1024
array:	.space 1024

	.text
 
# Open File
open:
	li	$v0, 13		# Open File Syscall
	la	$a0, file	# Load File Name
	li	$a1, 0		# Read-only Flag
	li	$a2, 0		# (ignored)
	syscall
	move	$s6, $v0	# Save File Descriptor
	blt	$v0, 0, err	# Goto Error
 
# Read Data
read:
	li	$v0, 14		# Read File Syscall
	move	$a0, $s6	# Load File Descriptor
	la	$a1, buffer	# Load Buffer Address
	li	$a2, 1024	# Buffer Size
	syscall
	
# Print Data
print: #not used
	
	
 	
# Close File
close:
	li	$v0, 16		# Close File Syscall
	move	$a0, $s6	# Load File Descriptor
	syscall
	j	done		# Goto End
 
# Error
err:
	li	$v0, 4		# Print String Syscall
	la	$a0, fnf	# Load Error String
	syscall
 
# Done(EVERYTHING IS IN THE BUFFER NOW)
done:
	la $t0, buffer #load buffer string 
	li $t4, 1024 #set byte size
	li $t2, 0 #set loop counter to 0
	la $t1, array #initialize the array that the buffer is being placed in. 
loop:
	lb $s0, 0($t0)
	beq $s0, 0, getLastElement #branch if character is null
	beq $s0, 45, skip #branch if character is -
	beq $s0, 13, skip #branch if character is \
	beq $s0, 10, skip #branch if character is n
	
	subi $s0, $s0, 48 #subtract to get the actual numerical value
	
	move $a0, $s0 #prepare for print of the value in the linked list
	li $v0, 1 #tell the system to print an integer 
	syscall #system call
	
	addi $t8, $t0, 1 #increment a secondary counter (keeps track of ending index
	lb $t8, 0($t8) #get the byte from the last index
	beq $t8, 0, skipPrint #skip the print if the value is 0 
	
	la $a0, arrow #load the array string
	li $v0, 4 #tell the system to print a string
	syscall #system call
	
skipPrint:
	sb $s0, 0($t1) #save byte
	addi $t9, $t9, 1 #counter for number of values (used later)
	addi $t1, $t1, 1 #increment the value in the array 
skip: #skip
	addi $t0, $t0, 1 #increment the value in memory (buffer) 
	addi $t2, $t2, 1 #increment counter 
	beq $t2, $t4, getLastElement #jump to get last element if it is finished
	
	j loop #jump to loop labek
	

getLastElement: #gets the last element of the linked list
	la $a0, msg #prepares msg to print
	li $v0, 4 #tell the system to print a string 
	syscall	 #system call
	
	la $t0, array #load the address
	subi $t9, $t9, 1 #evalate the end index
	add $t0, $t0, $t9 #advance the memory address of the array
	lb $a0, 0($t0) #get the value at the end of the Linked list
	li $v0, 1 #tell the system to print an integer
	syscall #system call

# Open (for writing) a file that does not exist
li   $v0, 13       # system call for open file
la   $a0, fout     # output file name
li   $a1, 1        # Open for writing (flags are 0: read, 1: write)
li   $a2, 0        # mode is ignored
syscall            # open a file (file descriptor returned in $v0)
move $s6, $v0      # save the file descriptor 
###############################################################
# Write to file just opened
li   $v0, 15       # system call for write to file
move $a0, $s6      # file descriptor 
la   $a1, array  # address of buffer from which to write
li $a2, 1024       # hardcoded buffer length
syscall            # write to file
###############################################################
# Close the file 
li   $v0, 16       # system call for close file
move $a0, $s6      # file descriptor to close
syscall            # close file
###############################################################


end: #ending statements
	la $a0, eol #print out end of list statement
	li $v0, 4 #tell the system to print a string
	syscall #system call
	
	move $a0, $t9 #move the counter value 
	li $v0, 1 #tell the system to print an integer 
	syscall #system call

	li $v0, 10 #tell the system to finish
	syscall #system call