fibo n digit

section .data
    newline db 10

section .bss
    n resb 2
    ans resb 8     ; increased buffer size for larger numbers

section .text
global _start

_start:
    ; read n
    mov rax, 0
    mov rdi, 0
    mov rsi, n
    mov rdx, 2
    syscall

    ; convert ASCII input to number
    movzx rax, byte [n]
    sub rax, '0'

    ; init first 2 elements
    mov rbx, 0     ; f0
    mov rcx, 1     ; f1

    ; store counter
    mov r8, rax
    mov rax, 1     ; i = 1

fib_loop:
    cmp rax, r8
    jge out_fib_loop

    mov rdx, rbx
    add rdx, rcx
    mov rbx, rcx
    mov rcx, rdx

    inc rax
    jmp fib_loop

out_fib_loop:
    ; Convert number in rcx to ASCII string
    mov rax, rcx    ; number to convert is in rcx
    mov rbx, 10     ; divisor
    mov rdi, ans    ; where to store the string
    add rdi, 7      ; point to end of buffer
    mov byte [rdi], 0   ; null terminator

    ; Convert to string (reverse order)
convert_loop:
    dec rdi
    xor rdx, rdx    ; clear rdx for division
    div rbx         ; divide rax by 10
    add dl, '0'     ; convert remainder to ASCII
    mov [rdi], dl   ; store digit
    test rax, rax   ; check if quotient is 0
    jnz convert_loop

    ; Calculate string length
    mov rdx, ans
    add rdx, 7      ; point to end of buffer
    sub rdx, rdi    ; rdx = length of string

    ; Print the result
    mov rax, 1
    mov rsi, rdi    ; point to start of number
    mov rdi, 1
    syscall

    ; Print newline
    mov rax, 1
    mov rdi, 1
    mov rsi, newline
    mov rdx, 1
    syscall

    ; Exit
    mov rax, 60
    xor rdi, rdi
    syscall