Question about StellarisWare, SW-RDK-S2E, stellarisif.c

stellarisif.c

static err_t
stellarisif_transmit(struct netif *netif, struct pbuf *p)
{
  int iBuf;
  unsigned char *pucBuf;
  unsigned long *pulBuf;
  struct pbuf *q;
  int iGather;
  unsigned long ulGather;
  unsigned char *pucGather;

........................... [omitted]

    /* Initialze a long pointer into the pbuf for 32-bit access. */
    pulBuf = (unsigned long *)&pucBuf[iBuf];

    /**
     * Copy words of pbuf data into the Tx FIFO, but don't go past
     * the end of the pbuf.
     *
     */
    while((iBuf + 4) <= q->len) {
      HWREG(ETH_BASE + MAC_O_DATA) = *pulBuf++;
      iBuf += 4;
    }

The above code is part of the latest version of the TI/Luminary StellarisWare.

I think it is a bug? And I hope to fix it with

  __packed unsigned long *pulBuf;

in the KEIL toolchain. (Tested.)

But due to my very limited C programming skill, I am afraid that, I might be doing something stupid. So I would like to learn something from our experts, please kindly give me some advices.

Is that, the __packed qualifier (in this case) leads to the lower performance?