20020911-1.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

extern void abort (void);
unsigned short c = 0x8000;
int main()
{
  if ((c-0x8000) < 0 || (c-0x8000) > 0x7fff)
    abort();
  return 0;
}