496 #define MEM_NIL &mem_z  macro
3936   mem_z.left = mem_z.right = MEM_NIL;  in mem_init()
3940   mem_root = MEM_NIL;  in mem_init()
3953     return MEM_NIL;  in mem_find()
3986   while (c != MEM_NIL)  in mem_insert()
4004   x->left = x->right = MEM_NIL;  in mem_insert()
4114   if (y->left != MEM_NIL)  in mem_rotate_left()
4118   if (y != MEM_NIL)  in mem_rotate_left()
4134   if (x != MEM_NIL)  in mem_rotate_left()
4151   if (y->right != MEM_NIL)  in mem_rotate_right()
4154   if (y != MEM_NIL)  in mem_rotate_right()
4167   if (x != MEM_NIL)  in mem_rotate_right()
4179   if (!z || z == MEM_NIL)  in mem_delete()
4182   if (z->left == MEM_NIL || z->right == MEM_NIL)  in mem_delete()
4187       while (y->left != MEM_NIL)  in mem_delete()
4191   if (y->left != MEM_NIL)  in mem_delete()
4545   if (m != MEM_NIL)  in mark_maybe_object()
4612   if (m != MEM_NIL)  in mark_maybe_pointer()
5017   if (m == MEM_NIL)  in valid_lisp_object_p()
6416     if (m == MEM_NIL)				\  in mark_object()
6484             if (m == MEM_NIL && !SUBRP (obj) && !main_thread_p (po))  in mark_object()