struct rtavl_node *s;

da[k] = 0;
pa[k++] = p;
for (;;)
  {
    da[k] = 1;
    pa[k++] = r;
    s = r->rtavl_link[1];
    if (s->rtavl_rtag == RTAVL_THREAD)
      break;
    r = s;
  }

if (s->rtavl_link[0] != NULL)
  {
    struct rtavl_node *t = s->rtavl_link[0];
    while (t->rtavl_rtag == RTAVL_CHILD)
      t = t->rtavl_link[1];
    t->rtavl_link[1] = p;
  }

p->rtavl_data = s->rtavl_data;
if (s->rtavl_link[0] != NULL)
  r->rtavl_link[1] = s->rtavl_link[0];
else
  {
    r->rtavl_rtag = RTAVL_THREAD;
    r->rtavl_link[1] = p;
  }

p = s;