/* Set the previous node pointer of a node  */
static void node_set_prev(lv_ll_t *ll_p, lv_ll_node_t *act, lv_ll_node_t *prev)
/* Set the previous node pointer of a node  */
static void node_set_prev(lv_ll_t *ll_p, lv_ll_node_t *act, lv_ll_node_t *prev)
{
    if(act == NULL) return;
    uint8_t * act8 = (uint8_t *)act;
    act8 += LL_PREV_P_OFFSET(ll_p);
    lv_ll_node_t ** act_node_p = (lv_ll_node_t **) act8;
    lv_ll_node_t ** prev_node_p = (lv_ll_node_t **) &prev;
    *act_node_p = *prev_node_p;
}