ARM, RISC-V контроллеры

/**
  * @brief function used to send data
  * @param  tpcb: tcp control block
  * @param  es: pointer on structure of type echoclient containing info on data 
  *             to be sent
  * @retval None 
  */
static void tcp_echoclient_send(struct tcp_pcb *tpcb, struct echoclient * es)
{
  struct pbuf *ptr;
  err_t wr_err = ERR_OK;
 
  while ((wr_err == ERR_OK) &&
         (es->p_tx != NULL) && 
         (es->p_tx->len <= tcp_sndbuf(tpcb)))
  {
    
    /* get pointer on pbuf from es structure */
    ptr = es->p_tx;
    /* enqueue data for transmission */
    wr_err = tcp_write(tpcb, ptr->payload, ptr->len, 1);
    
    if (wr_err == ERR_OK)
    { 
      /* continue with next pbuf in chain (if any) */
      es->p_tx = ptr->next;
      
      if(es->p_tx != NULL)
      {
        /* increment reference count for es->p */
        pbuf_ref(es->p_tx);
      }
      
      /* free pbuf: will free pbufs up to es->p (because es->p has a reference count > 0) */
      pbuf_free(ptr);
   }
   else if(wr_err == ERR_MEM)
   {
      /* we are low on memory, try later, defer to poll */
     es->p_tx = ptr;
   }
   else
   {
     /* other problem ?? */
   }
  }
}