src = valptr(set->page, cnt);
nxt -= src->len + sizeof(BtVal);
memcpy ((unsigned char *)bt->frame + nxt, src, src->len + sizeof(BtVal));
src = valptr(set->page, cnt);
nxt -= src->len + sizeof(BtVal);
memcpy ((unsigned char *)bt->frame + nxt, src, src->len + sizeof(BtVal));