MAX_RADIX EQU 18
jmp main

;ds:si - input buf
;df - direction
proc_writeln:
    pusha
    mov ah, 0Eh
    write:
        lodsb
        test al,al
        jz exit_write
        int 10h
        jmp write
    exit_write:
        ;newline
        mov al, 0Dh
        int 10h
        mov al, 0Ah
        int 10h
        popa
        ret


;es:di - output buf
;df - direction
;cx - max buffer size
proc_readln:
    pusha
    read:
        mov ah, 0
        int 16h
        cmp al, 13
        jz exit_read
        stosb
        loop read

    exit_read:
        mov al, 0 ;;\0
        stosb

        mov ah, 0Eh

        ;newline
        mov al, 0Dh
        int 10h
        mov al, 0Ah
        int 10h

        popa
        ret

;ds:si - char buf
;es:di - integer buf
;df - direction
proc_to_integer:
    pusha
    transform_integer:
        lodsb
        test al,al
        jz transform_integer_exit

        cmp al, 2Fh                     ;;validation start
        jng transform_integer_error
        cmp al, 39h
        jg transform_integer_error      ;;validation end

        sub al, 30h
        stosb
        jmp transform_integer

    transform_integer_error:
        stc

    transform_integer_exit:
        mov al, '$'
        stosb

        popa
        ret

;ds:si - integer buf
;es:di - char buf
;df - direction
proc_to_char:
    pusha
    transform_char:
        lodsb
        cmp al, '$'
        jz transform_char_exit

        add al, 30h
        stosb
        jmp transform_char

    transform_char_exit:
        mov al, 0
        stosb

        popa
        ret

;es:di - buf
proc_reverse:
    pusha
    lea si, di+MAX_RADIX-1

    reverse_loop:
        mov al, [di]
        mov ah, [si]
        mov [di], ah
        mov [si], al

        inc di
        dec si
        cmp di, si
        jb reverse_loop

    popa
    ret


;es:di - output buf
proc_read_integer:
    pusha

    mov cx, MAX_RADIX - 1

    cld
    call proc_readln
    mov ax, es
    mov ds, ax
    mov si, di
    call proc_to_integer
    jc read_error

    call proc_reverse

    popa
    ret

    read_error:
        lea si, Err_not_integer
        call proc_writeln
        popa
        call proc_read_integer
        ret

;ds:si - output buf
proc_write_integer:
    pusha

    add si, MAX_RADIX - 1
    mov ax, ds
    mov es, ax
    mov di, si
    call proc_to_char

    call proc_writeln
    popa
    ret

;;stack top - op_1
;;next - op_2
;;next - res
proc_sum:
    pusha
    mov bp, sp



    ret

main:
    mov ax, cs
    mov ds, ax
    lea si, Invite_1
    call proc_writeln

    mov ax, cs
    mov es, ax
    lea di, op_1
    call proc_read_integer

    lea si, Invite_2
    call proc_writeln

    lea di, op_2
    call proc_read_integer

    push offset res
    push offset op_2
    push offset op_1
    call proc_sum


    lea si, Res_message
    call proc_writeln

    lea si, op_1
    call proc_write_integer

    mov ah, 4Ch
    int 21h

Invite_1 db 'Enter first number: ', 0
Invite_2 db 'Enter second number: ', 0
Res_message db 'Result is: ', 0
Err_not_integer db 'This is not a number. Try again: ', 0

op_1 db MAX_RADIX dup('$')
op_2 db MAX_RADIX dup('$')
res db MAX_RADIX dup('$')