sum of multiples of 3 and 5 smaller than 1000

global _start
section .text
    _start:
                        mov             cx, 0
                        mov             ax, 0
    _loop:
                        cmp cx, 1000
                        je  _done
                        add cx, 3   ; next multiple of 3
                        add ax, cx
                        add cx, 2   ; next multiple of 5
                        add ax, cx  ; #thinkoutofthebox
                        sub cx, 5   ; reset
                        jmp _loop

    _done: