input_to_ax macro
  local _input, _not_first_symbol, _incorrect, _correct, _clear_symb, _input_end, _process_number, _neg_flag, _end_of_processing
  push bx
  push cx
  push dx
  xor cx, cx
  xor bx, bx
  xor dx, dx
_input:
  xor ax, ax
  mov ah, 01
  int 21h
  cmp al, 0Dh
  je _correct
  cmp al, 08h
  je _correct
  cmp cx, 0
  jg _not_first_symbol
  cmp al, 2Dh
  je _correct
_not_first_symbol:
  cmp al, 30h
  jl _incorrect
  cmp al, 39h
  jg _incorrect
  jmp _correct
_incorrect:
  mov dl, 08h
  mov ah, 02h
  int 21h
  mov dl, 20h
  mov ah, 02h
  int 21h
  mov dl, 08h
  mov ah, 02h
  int 21h
  jmp _input
_correct:
  cmp al, 0Dh ; ENTER
  je _input_end
  cmp al, 08h ; BACKSPACE
  je _clear_symb
  mov ah, 0
  push ax
  inc cx
  jmp _input
_clear_symb:
  cmp cx, 0
  je _input
  pop ax
  dec cx
  mov dl, 20h
  mov ah, 02h
  int 21h
  mov dl, 08h
  mov ah, 02h
  int 21h
  jmp _input
_input_end:
  xor dx, dx
  mov bx, 1
  cmp cx, 0
  jne _process_number
  mov ax, 0
  jmp _end_of_processing
_process_number:
  pop ax
  cmp al, 02dh ; - sign
  jne _neg_flag
  neg dx
  jmp _end_of_processing
_neg_flag:
  sub al, 30h
  mov ah, 0
  push dx
  mul bx
  pop dx
  add dx, ax
  mov ax, bx
  mov bx, 10
  push dx
  mul bx
  pop dx
  mov bx, ax
  loop _process_number
_end_of_processing:
  mov ax, dx
  pop dx
  pop cx
  pop bx


endm input_to_ax