section .bss
	value	resb	32
section .text
    GLOBAL _start

_start:
	mov	rax,	0
	mov	rdi,	0
	mov	rsi,	value
	mov	rdx,	32
	syscall
	mov	rdi,	value
	call _strlen
	sub	rax,	1
	mov	rcx,	rax
	lea	rsi,	[value]
	call string_to_int

    push qword rax         ; -> 1346269
    call fibonacci
    add rsp, 8

    call write_rax

    mov edi, 0                  ; return 0 (success)
    mov eax, 60                 ; sys_exit
    syscall

fibonacci:
    push rbp
    push rbx

    mov rbp, rsp
    add rbp, 24
    mov ebx, [rbp]

    cmp     EBX,0       ; Check for base case
    je     base        ; It is base if (n <= 1)

    cmp     EBX,1
    je base2

    lea ecx,[ebx-1]
    push rcx
    call    fibonacci   ; Calculate fibonacci for (EBX - 1)
    pop rcx

    push rax
    lea ecx,[ebx-2]
    push rcx
    call    fibonacci   ; Calculate fibonacci for (EBX - 2)
    pop rcx
    pop rcx
    add eax,ecx         ; eax = fibonacci(N-2) + fibonacci(N-1)

    jmp end
    base:               ; Base case
    mov EAX,2
    jmp end           ; The result would be 1

    base2:               ; Base case
    mov EAX,1           ; The result would be 1

    end:
    pop rbx
    pop rbp
    ret

write_rax:
mov rsi, rsp                ; Keyword: Red Zone (https://en.wikipedia.org/wiki/Red_zone_%28computing%29)

    sub rsi, 1
    mov byte [rsi], `\n`        ; Line feed

    mov ecx, 10                 ; Divisor

    .L1:
    xor rdx, rdx
    div rcx                     ; EDX:EAX / ECX -> EAX, remainder EDX
    or dl, 48                 ; Convert remainder to ASCII
    sub rsi, 1
    mov [rsi], dl               ; Store remainder reversed on the stack
    test rax, rax
    jne .L1

    mov rdx, rsp                ; RDX: message string length
    sub rdx, rsi
    mov rdi, 1                  ; RDI=1: stdout
    mov rax, 1                  ; sys_write
    syscall                     ; /usr/include/x86_64-linux-gnu/asm/unistd_64.h

    ret

string_to_int:
    xor rbx,rbx    ; czysczę ebx
    l2:
        movzx rax,byte[rsi] ; ???
        inc rsi         ; esi ++
        sub al,'0'      ; najmniej znaczący bit - 48
        imul rbx,10     ; mnożenie ebax = ebax * 10
        add rbx,rax     ; ebx += eax
        loop l2         ; while (--ecx)
    mov rax, rbx        ; eax = ebx
    ret

_strlen:

  push  rcx            ; save and clear out counter
  xor   rcx, rcx

_strlen_next:

  cmp   [rdi], byte 0  ; null byte yet?
  jz    _strlen_null   ; yes, get out

  inc   rcx            ; char is ok, count it
  inc   rdi            ; move to next char
  jmp   _strlen_next   ; process again

_strlen_null:

  mov   rax, rcx       ; rcx = the length (put in rax)

  pop   rcx            ; restore rcx
  ret                  ; get out