finished

# char array[100];
# int size = 100;
#
# void main() {
#     sieve(array, size);
#     for (int i = 0; i < size; i++)
#         if (array[i] == 1)
#             printf("%d\n", i);
# }
#
# void sieve(char * array, int size) {
#     array[0] = 0;
#     array[1] = 0;
#     for (int i = 2; i < size; i++)
#         array[i] = 1;
#     for (int i = 2; i * i < size; i++)
#         if (array[i] == 1)
#             for (int j = 2 * i; j < size; j += i)
#                 array[j] = 0;
# }

.data

array:	.space 100
size:	.word 100

.text

main:	la	$s0, array
	lw	$s1, size
	addi	$a0, $s0, 0
	addi	$a1, $s1, 0
	jal	sieve
	add	$t0, $zero, $zero
m_loop:	slt	$t1, $t0, $s1
	beq	$t1, $zero, m_done
	add	$t1, $s0, $t0
	lbu	$t1, 0($t1)
	beq	$t1, $zero, m_skip
	addi	$v0, $zero, 1
	addi	$a0, $t0, 0
	syscall				# print integer
	addi	$v0, $zero, 11
	addi	$a0, $zero, 10
	syscall				# print character '\n'
m_skip:	addi	$t0, $t0, 1
	j 	m_loop
m_done:	addi	$v0, $zero, 10
	syscall				# terminate the program

					# populate array
sieve:	la	$a0, array
	lw	$t1, 0($a0)		# load first value
	add	$t0, $zero, $zero	# set index to 0
loop1:	beq	$t0, $s1, next1		# break when we we get to end
	addi	$t1, $zero, 1		# set entry to 1
	sb	$t1, 0($a0)		# store entry at index
	addi	$a0, $a0, 1		# increment pointer
	addi	$t0, $t0, 1		# increment index
	j	loop1			# loop

					# remove non-prime
next1:	la	$a0, array
	lw	$t1, 0($a0)		# load first value
	add	$t0, $zero, $zero	# set index to 0
	add	$t1, $zero, $zero	# zero data
	sb	$t1, 0($a0)		# 0 is not prime
	addi	$t0, $t0, 1		# increment counter
	addi	$a0, $a0, 1		# increment pointer
	sb	$t1, 0($a0)		# 1 is not prime
	addi	$t0, $t0, 1		# increment counter
	addi	$a0, $a0, 1		# increment pointer

	addi	$t2, $zero, 2		# first prime

loop2:	div	$s1, $t2		# is this the largest factor?
	mflo	$t3			# quotient
	blt	$t3, $t2, s_done	# finished seiving
	add	$t0, $zero, $zero	# reset counter
	la	$a0, array		# reset pointer
	add	$t0, $t0, $t2		# set counter to current prime
	add	$a0, $a0, $t2		# set pointer to current position
loop3:	beq	$t0, $s1, inc		# end of array
	add	$a0, $a0, $t2		# increment pointer
	add	$t1, $zero, $zero	# set entry to 0 (not prime)
	sb	$t1, 0($a0)		# store entry at index
	addi	$t0, $t0, 1		# increment index
	j	loop3			# loop
inc:	addi	$t2, $t2, 1		# increment factor
	j	loop2			# loop

s_done:	jr	$ra			# return to main