.data

array: .word 0:20

endline: .asciiz "\n"
firstnumber: .asciiz "Give me the first number of the sequence"
step: .asciiz "Give me the step of this sequence"
space: .asciiz " "
sum: .asciiz "The sum of the 20  first terms of the sequence is:"


.text

main:

la $t0, array 		#we are gonna use $t0 as a pointer


la $a0, firstnumber
li $v0, 4
syscall              #Print firstnumber message

li $v0, 5            #Get First integer from keyboard
syscall
sw $a0, ($t0)		#saves the first integer to the first array Cell



la $a0, step
li $v0, 4
syscall              #Print step message


li $v1, 5            #Get step from keyboard
syscall
move $t1 , $v1


li $t2 , 0          #counter for array iteration
li $t3 , 20         #limit for array iteration
li $t5, 0			#initialize sum of sequence

firstloop:

blt $t2,$t3,secondloop #if counter is out of bounds, do to second loop

lw $t4, array + $t2 #load number from iterator's position

add $t2,$t2,4       #ready to iterate to the next array cell

add $t4, $t4, $t1   #calculate next sequence number

sw $t4, array + $t2 #store next number to the next array cell

j firstloop



secondloop:

bltz $t2, result

sub $t2, $t2, 4

lw $t4,  array + $t2

move $a0, $t4
li $v0, 1

add $t5, $t5, $t4

j secondloop

result:

li $v0, 10			#exit system call
syscall