; dbg_cd03.asm -- the same program, but the breakpoint is the two-byte CD 03.
bits 16
org 0x100
    mov ax, 1111h
    db 0CDh, 03h            ; CD 03  (NASM's `int 3` would emit exactly this)
    mov ax, 2222h
    mov ax, 4C00h
    int 21h