section .data 
    choice: db "Enter your choice: 1.Addition 2.Subtraction 3.Multiplication 4.Division", 0Ah
    choicelen: equ $-choice

    msg: db "The Addition is: ", 0Ah
    len: equ $-msg

    msg1: db "The Subtraction is: ", 0Ah
    len1: equ $-msg1

    msg2: db "The Multiplication is: ", 0Ah
    len2: equ $-msg2

    msg3: db "The Division is: ", 0Ah
    len3: equ $-msg3

    div_error_msg: db "Error: Division by zero!", 0Ah
    div_error_len: equ $-div_error_msg

    arr dq 0x2222222222222222, 0x11111, 0x1111, 0x1111, 0x1111
    temp dq 0

section .bss
    count: resb 1
    result: resb 17
    result1: resb 17
    result2: resb 17
    result3: resb 17

%macro disp 2 
    mov rax, 1
    mov rdi, 1
    mov rsi, %1
    mov rdx, %2
    syscall
%endmacro

section .text
    global _start

_start:

    disp choice, choicelen
    mov rax, 0
    mov rdi, 0
    mov rsi, temp
    mov rdx, 1
    syscall

    mov al, [temp]   ; Load first byte of user input
    cmp al, '1'      ; Compare with '1'
    je ch1
    cmp al, '2'
    je ch2
    cmp al, '3'
    je ch3
    cmp al, '4'
    je ch4
    jmp exit         ; Invalid input, exit

ch1: 
    call Addition
    jmp exit
ch2: 
    call Subtraction
    jmp exit
ch3: 
    call Multiplication
    jmp exit
ch4: 
    call Division
    jmp exit

Addition:
    disp msg, len
    mov byte [count], 5
    mov rax, 0
    mov rsi, arr

loop1:
    add rax, [rsi]
    add rsi, 8
    dec byte [count]
    jnz loop1

    mov rbx, rax 
    mov rsi, result
    call display
    disp result, 17
    ret 

Subtraction:
    disp msg1, len1
    mov byte [count], 4
    mov rsi, arr
    mov rax, [rsi]  
    add rsi, 8 

loop2:
    sub rax, [rsi] 
    add rsi, 8
    dec byte [count]
    jnz loop2

    mov rbx, rax
    mov rsi, result1
    call display
    disp result1, 17
    ret 

Multiplication:
    disp msg2, len2 
    mov byte [count], 4
    mov rsi, arr
    mov rax, [rsi]
    add rsi, 8

loop3:
    mov rcx, [rsi]
    mul rcx 
    add rsi, 8
    dec byte [count]
    jnz loop3

    mov rbx, rax
    mov rsi, result2
    call display
    disp result2, 17
    ret

Division:
    disp msg3, len3
    mov byte [count], 4
    mov rsi, arr
    mov rax, [rsi]
    add rsi, 8

loop4:
    mov rcx, [rsi]
    cmp rcx, 0      ; Check for division by zero
    je div_error
    div rcx
    add rsi, 8
    dec byte [count]
    jnz loop4

    mov rbx, rax
    mov rsi, result3
    call display
    disp result3, 17
    ret 

div_error:
    disp div_error_msg, div_error_len
    jmp exit

display: 
    mov rdi, rsi     ; Destination pointer
    mov rcx, 0       ; Digit count

convert:
    mov rdx, 0       ; Clear remainder
    mov rbx, 10
    div rbx          ; RAX / 10, remainder in RDX
    add dl, '0'      ; Convert remainder to ASCII
    push rdx         ; Store character
    inc rcx
    test rax, rax
    jnz convert

write_digits:
    pop rax
    mov [rdi], al
    inc rdi
    loop write_digits

    mov byte [rdi], 0Ah  ; Newline character
    ret

exit:
    mov rax, 60
    xor rdi, rdi
    syscall