host_to_network (pulong -w target, ulong source)
{
  reverse (target, source);
}

network_to_host (pulong -w target, ulong source)
{
  reverse (target, source);
}

reverse host%, network% (pulong -w target, ulong source)
{
  asm (X86/64) / eax, ecx
  {
    mov eax, source;                                                           /* eax = source;      */
    bswap eax;                                                                 /* eax = bswap (eax); */

    mov ecx, target;                                                           /* ecx = target;      */
    mov (ecx), eax;                                                            /* ecx^ = eax;        */
  }
}