.data
    msg1: .asciiz "Give n: "
    msg2: .asciiz "give me a0: "
.text

main:
    li $v0, 4
    la $a0, msg2
    syscall

    li $v0, 5
    syscall
    move $t7, $v0       #move to t7

    li $v0, 4
    la $a0, msg1
    syscall

    li $v0, 5
    syscall
    move $a0, $v0       #move to a0

    jal fib             #call fib
    #add $a0, $zero, $zero
    add $a0, $v0, $zero
    li $v0, 1
    syscall

    li $v0, 10
    syscall

fib:
    sub $sp, $sp, 4     #sp -12
    sw $ra, ($sp)           #ra trzymamy pod sp
    add $s0, $a0, $zero     #s0 = a0 czyli userinput

    addi $t1, $zero, 1      #t1 = 1
    beq $s0 $zero, return0      #jesli s0 == 0 to return0

    sub $a0, $s0, 1         # s0-- wynik do a0

    jal fib             #zapętl do gory

    mul $s1, $v0, 2     #s1 = fib(y-1)
    add $s1, $s1, 1
    move $v0, $s1

exitfib:
    lw $ra, ($sp)
    addi $sp, $sp, 4
    jr $ra

return0:
    move $v0, $t7
    j exitfib