// Read IP address of the peer
  addr[0] = UDPHeader.u.header.addr[0];
  addr[1] = UDPHeader.u.header.addr[1];
  addr[2] = UDPHeader.u.header.addr[2];
  addr[3] = UDPHeader.u.header.addr[3];

  // Read Port number of the peer
  *port = UDPHeader.u.stream[6];
  *port = (*port << 8) + UDPHeader.u.stream[7];

  // Increase read pointer by 8, because already read as UDP header size
  rd_ptr.lVal += 8;

  // Calculate UDP data copy pointer
  offset = ((UINT)(rd_ptr.lVal & RMASK[s]));

  // Calculate data size of current UDP Packet from UDP header
  size = size - 8;

  // Copy one UDP data packet to user-specific buffer
  ret = read_data(s, offset, buf, (u_int)size);

  // Increase read pointer by UDP packet data size
  rd_ptr.lVal += ret;
  }
else if ((READ_VALUE(OPT_PROTOCOL(s)) & 0x07) == SOCK_IPL_RAW)	 // When IP layer RAW mode data
  {
  // Copy W3100A IP Raw header
  read_data(s, offset, UDPHeader.u.stream, 6);

  // Read IP layer RAW Packet size
  size = UDPHeader.u.stream[0];
  size = (size << 8) + UDPHeader.u.stream[1];

  // Read IP address of the peer
  addr[0] = UDPHeader.u.header.addr[0];
  addr[1] = UDPHeader.u.header.addr[1];
  addr[2] = UDPHeader.u.header.addr[2];
  addr[3] = UDPHeader.u.header.addr[3];

  // Increase read pointer by 6, because already read as IP RAW header size
  rd_ptr.lVal += 6;

  // Calculate IP layer raw mode data pointer
  offset = ((UINT)(rd_ptr.lVal & RMASK[s]));

  // Copy one IP Raw data packet to user-specific buffer
  ret = read_data(s, offset, buf, (u_int)size);
  rd_ptr.lVal = rd_ptr.lVal + (ret - 4);
  }

  // Update rx_rd_ptr
  WRITE_VALUE(RX_RD_PTR(s), rd_ptr.cVal[3]);
  WRITE_VALUE(RX_RD_PTR(s) + SA_OFFSET(1), rd_ptr.cVal[2]);
  WRITE_VALUE(RX_RD_PTR(s) + SA_OFFSET(2), rd_ptr.cVal[1]);
  WRITE_VALUE(RX_RD_PTR(s) + SA_OFFSET(3), rd_ptr.cVal[0]);

  // RECV
  WRITE_VALUE(COMMAND(s), CRECV);

// Real received size return
return(ret);
}

/*
****************************************************************************************************
*              Channel closing function.
*
* Description : Function for closing the connection of the designated channel.
* Arguments   : s - channel number
* Returns     : None
* Note        : API Function
****************************************************************************************************
*/
void close(SOCKET s)
{
u_int len;
short sAttempts = 0;

I_STATUS[s] = 0;

if (select(s, SEL_CONTROL) == SOCK_CLOSED)
  return;	   // Already closed

// When closing, if there's data which have not processed, Insert some source codes to handle this
// Or before application call close(), handle those data first and call close() later.

len = select(s, SEL_SEND);
if (len == SSIZE[s])
  {
  // CLOSE
  WRITE_VALUE(COMMAND(s), CCLOSE);
  // TODO: The 'SCLOSED' status value is only set briefly as part of the close,
  // and will otherwise quickly return to normal.  That means your code might
  // become 'stuck' at this point even if the packet has closed normally.
  // Rather than a while() call, it might be preferred to time out on this
  // close check and return to the application after some time.
  while(!(I_STATUS[s] & SCLOSED))
  {
  	  sAttempts++;
      if( sAttempts > 10 )
      {
      	break;
      }
  	  I2CHIP_POLL_ISR(in4_isr_i2chip);
  }
  }
}

u_char tx_empty(SOCKET s)
{
	return (select(s, SEL_SEND) == SSIZE[s]);
}

/*
****************************************************************************************************
*              Channel closing function.
*
* Description : Function for closing the connection of the designated channel.
* Arguments   : s - channel number
* Returns     : None
* Note        : API Function
****************************************************************************************************
*/
char reset_sock(SOCKET s)
{
u_char c;

c = 1 << s;

// RESET
WRITE_VALUE(RESETSOCK, c);
return	(1);
}

/*
****************************************************************************************************
*             Function handling the channel socket information.
*
* Description : Return socket information of designated channel
* Arguments   : s    - channel number
*               func - SEL_CONTROL(0x00) -> return socket status
*                      SEL_SEND(0x01)    -> return free transmit buffer size
*                      SEL_RECV(0x02)    -> return received data size
* Returns     : socket status or free transmit buffer size or received data size
* Note        : API Function
****************************************************************************************************
*/
u_int select(SOCKET s, u_char func)
{
u_int val;
union un_l2cval rd_ptr, wr_ptr, ack_ptr;
u_char k;

switch (func)
  {
  // socket status information
  case SEL_CONTROL :
	 val = READ_VALUE(SOCK_STATUS(s));
	 break;

  // Calculate send free buffer size
  case SEL_SEND :
	 disable();
	 k = READ_VALUE(SHADOW_TXWR_PTR(s));
	 WINDOW_RESTORE_BASE;  // Needed whenever we touch a shadow ptr; different window.
	 delay0(2);
	 wr_ptr.cVal[3] = READ_VALUE(TX_WR_PTR(s));
	 wr_ptr.cVal[2] = READ_VALUE(TX_WR_PTR(s) + SA_OFFSET(1));
	 wr_ptr.cVal[1] = READ_VALUE(TX_WR_PTR(s) + SA_OFFSET(2));
	 wr_ptr.cVal[0] = READ_VALUE(TX_WR_PTR(s) + SA_OFFSET(3));

	 if (( READ_VALUE(OPT_PROTOCOL(s)) & 0x07) == SOCK_STREAM)	// TCP
		{
		k = READ_VALUE(SHADOW_TXACK_PTR(s));
		WINDOW_RESTORE_BASE;  // Needed whenever we touch a shadow ptr; different window.
		delay0(2);
		ack_ptr.cVal[3] = READ_VALUE(TX_ACK_PTR(s));
		ack_ptr.cVal[2] = READ_VALUE(TX_ACK_PTR(s) + SA_OFFSET(1));
		ack_ptr.cVal[1] = READ_VALUE(TX_ACK_PTR(s) + SA_OFFSET(2));
		ack_ptr.cVal[0] = READ_VALUE(TX_ACK_PTR(s) + SA_OFFSET(3));
		enable();

		if (wr_ptr.lVal >= ack_ptr.lVal)
        val = (u_int)(SSIZE[s] - (wr_ptr.lVal - ack_ptr.lVal));
		else
        val = (u_int)(SSIZE[s] - (0 - ack_ptr.lVal + wr_ptr.lVal));
		}
	 else											// UDP, IP RAW ... (except TCP)
		{
		k = READ_VALUE(SHADOW_TXRD_PTR(s));
		WINDOW_RESTORE_BASE;  // Needed whenever we touch a shadow ptr; different window.
		delay0(2);
		rd_ptr.cVal[3] = READ_VALUE(TX_RD_PTR(s));
		rd_ptr.cVal[2] = READ_VALUE(TX_RD_PTR(s) + SA_OFFSET(1));
		rd_ptr.cVal[1] = READ_VALUE(TX_RD_PTR(s) + SA_OFFSET(2));
		rd_ptr.cVal[0] = READ_VALUE(TX_RD_PTR(s) + SA_OFFSET(3));
		enable();

		if (wr_ptr.lVal >= rd_ptr.lVal)
        val = (u_int)(SSIZE[s] - (wr_ptr.lVal - rd_ptr.lVal));
		else
        val = (u_int)(SSIZE[s] - (0 - rd_ptr.lVal + wr_ptr.lVal));
		}
	 break;

  //  Calculate received data size
  case SEL_RECV :
	 disable();
	 k = READ_VALUE(SHADOW_RXWR_PTR(s));
	 WINDOW_RESTORE_BASE;  // Needed whenever we touch a shadow ptr; different window.
	 delay0(2);
	 wr_ptr.cVal[3] = READ_VALUE(RX_WR_PTR(s));
	 wr_ptr.cVal[2] = READ_VALUE(RX_WR_PTR(s) + SA_OFFSET(1));
	 wr_ptr.cVal[1] = READ_VALUE(RX_WR_PTR(s) + SA_OFFSET(2));
	 wr_ptr.cVal[0] = READ_VALUE(RX_WR_PTR(s) + SA_OFFSET(3));

	 k = READ_VALUE(SHADOW_RXRD_PTR(s));
    WINDOW_RESTORE_BASE;  // Needed whenever we touch a shadow ptr; different window.
	 delay0(2);
	 rd_ptr.cVal[3] = READ_VALUE(RX_RD_PTR(s));
	 rd_ptr.cVal[2] = READ_VALUE(RX_RD_PTR(s) + SA_OFFSET(1));
	 rd_ptr.cVal[1] = READ_VALUE(RX_RD_PTR(s) + SA_OFFSET(2));
	 rd_ptr.cVal[0] = READ_VALUE(RX_RD_PTR(s) + SA_OFFSET(3));
	 enable();

	 if (wr_ptr.lVal == rd_ptr.lVal)
      val = 0;
	 else if (wr_ptr.lVal > rd_ptr.lVal)
      val = (u_int)(wr_ptr.lVal - rd_ptr.lVal);
	 else
      val = (u_int)(0 - rd_ptr.lVal + wr_ptr.lVal);
	 break;

  default :
	 val = -1;
	 break;
  }
// Suppress compiler errors that k is not used
k = k;
return(val);
}

//
//	unsigned char dma_read_i2chip (unsigned int i2_segm, unsigned int i2_offs,
//	unsigned int cnt, unsigned int des_segm, unsigned int des_offs);
//	Using DMA0 to read data from i2chip buffer into destination SRAM.
//	where:
//		unsigned int cnt = number of sectors, 512-byte per sector
//		unsigned int des_segm = segment of destination SRAM data memory
//		unsigned int des_offs = offset of destination SRAM data memory
//		unsigned int i2_segm = segment of i2chip buffer mapped in memory
//		unsigned int i2_offs = offset of i2chip buffer mapped in memory
//	 return DMA counter value
//
unsigned int dma_read_i2chip(u_char far* i2_src, u_char far* des, u_int cnt)
{
	u_int des_segm, des_offs;
   u_int i2_segm, i2_offs;
   u_long temp;

   temp = ((long)FP_SEG(des) << 4) + ((long)FP_OFF(des));
   des_segm = (u_int)(temp >> 16);
   des_offs = (u_int)(temp & 0xffff);

   temp = ((long)FP_SEG(i2_src) << 4) + ((long)FP_OFF(i2_src));
   i2_segm = (u_int)(temp >> 16);
   i2_offs = (u_int)(temp & 0xffff);

	outport(0xffc6, des_segm);   /* D0DSTH destination SRAM segment */
	outport(0xffc4, des_offs);   /* D0DSTL destination SRAM offset */
	outport(0xffc2, i2_segm);   /* D0SRCH=SP0RD */
	outport(0xffc0, i2_offs);   /* D0SRCL=SP0RD */
	outport(0xffc8, cnt);   // D0TC counter
	outport(0xfff8,0x0504);	// PLLCON, 0203=10M,050f=40M, 051f=80MHz
// DMA0 mem-mem, 16-bit, unsync, Start moving data line below
	outport(0xffca, 0xb60e);   /* D0CON 1011 0110 0000 1111 */
//	outport(0xffca, 0xb42e);         // 1011 0100 0010 1110
	while( inport(0xffc8) ); /* D0TC counter=0, DMA complete */
	outport(0xfff8,0x051f);	// PLLCON, 0203=10M,050f=40M, 051f=80MHz
return( inport(0xffc8) ); // counter
}

//
//	unsigned int dma_write_i2chip (unsigned int src_segm, unsigned int src_offs,
//	unsigned int cnt, unsigned int i2_segm, unsigned int i2_offs);
//	Using DMA0 to write data from memory into i2chip.
//	where:
//		unsigned int cnt = number of 16-bit DMA transfers
//		unsigned int src_segm = segment of the source SRAM data memory
//		unsigned int src_offs = offset of the source SRAM data memory
//		unsigned int i2_segm = segment of i2chip buffer mapped in memory
//		unsigned int i2_offs = offset of i2chip buffer mapped in memory
//	 return DMA counter value
//
unsigned int dma_write_i2chip(u_char far* src, u_char far* i2_dest, u_int cnt)
{
	u_int src_segm, src_offs;
   u_int i2_segm, i2_offs;
   u_long temp;

   temp = (FP_SEG(src) << 4) + (FP_OFF(src));
   src_segm = (u_int)(temp >> 4);
   src_offs = (u_int)(temp & 0xffff);

   temp = (FP_SEG(i2_dest) << 4) + (FP_OFF(i2_dest));
   i2_segm = (u_int)(temp >> 4);
   i2_offs = (u_int)(temp & 0xffff);

	outport(0xffc8, cnt);   // D0TC counter
	outport(0xffc6, i2_segm); // D0DSTH=i2chip buffer segment
	outport(0xffc4, i2_offs); // D0DSTL=i2chip buffer offset
	outport(0xffc2, src_segm);   /* D0SRCH=SP0RD */
	outport(0xffc0, src_offs);   /* D0SRCL=SP0RD */
//	outport(0xfff8,0x050f);	// PLLCON, 0203=10M,050f=40M, 051f=80MHz
// DMA0 mem-mem, 16-bit, unsync, Start moving data line below
	outport(0xffca, 0xb60f);   /* D0CON 1011 0110 0000 1111 */
	while( inport(0xffc8) ); /* D0TC counter=0, DMA complete */
//	outport(0xfff8,0x051f);	// PLLCON, 0203=10M,050f=40M, 051f=80MHz

return( inport(0xffc8) ); // counter
}

/*
****************************************************************************************************
*              Copies the receive buffer data of the W3100A to the system buffer.
*
* Description : Copies the receive buffer data of the W3100A to the system buffer.
*    It is called from the recv()or recvfrom() function.
* Arguments   : s   - channel number
*               src - receive buffer pointer of W3100A
*               dst - system buffer pointer
*               len - data size to copy
* Returns     : copied data size
* Note        : Internal Function
****************************************************************************************************
*/
u_int read_data(SOCKET s, u_int offset, u_char far * dst, u_int len)
{
	u_int i, size, size1;
   u_char far* src = (u_char far*)(MK_FP_WINDOW(RECV_DATA_BUF,
                                        RBUFBASEADDRESS[s] + offset));
//   src = (u_char far*)(MK_FP_WINDOW(RECV_DATA_BUF,
//                                        0));

	if (len == 0)
   {
   	WINDOW_RESTORE_BASE;    // Needed whenever we do a call to MK_FP_WINDOW.
  		return 0;
   }

   if ((offset + len) > RSIZE[s])
   {
		size = (u_int)(RSIZE[s] - offset);

  		if (size > TERN_RDMA_THRES)
  		{
  			dma_read_i2chip(src, dst, size);
  		}
  		else
      {
  	 		for (i = 0; i < size; i++)
    		{
 	 			*dst++ = READ_VALUE(src);
            WINDOW_PTR_INC(src);

	 		}
  		}

	  size1 = len - size;
     src = (u_char far *)(MK_FP_WINDOW(RECV_DATA_BUF, (RBUFBASEADDRESS[s])));

     if (size1 > TERN_RDMA_THRES)
     {
     		dma_read_i2chip(src, dst, size);
  	  }
     else
  	  {
  			for (i = 0; i < size1; i++)
   		{
	 			*dst++ = READ_VALUE(src);
            WINDOW_PTR_INC(src);
   		}
  		}
	}
   else
   {
	 if (len > TERN_RDMA_THRES)
    {
  		dma_read_i2chip(src, dst, size);
    }
    else
    {
  		for (i = 0; i < len; i++)
    	{
  	 		*dst++ = READ_VALUE(src);
         WINDOW_PTR_INC(src);
	 	}
    }
   }
   WINDOW_RESTORE_BASE;    // Needed whenever we do a call to MK_FP_WINDOW.
	return len;
}


/*
****************************************************************************************************
*              Copies the system buffer data to the transmit buffer of the W3100A.
*
* Description : Copies the system buffer data to the transmit buffer of the W3100A.
*               It is called from the send_in()or sendto_in() function.
* Arguments   : s   - channel number
*               src - system buffer pointer
*               dst - send buffer pointer of W3100A
*               len - data size to copy
* Returns     : copied data size
* Note        : Internal Function
****************************************************************************************************
*/
u_int write_data(SOCKET s, u_char far * src, u_int offset, u_int len)
{
	u_int i, size, size1;
	u_char far* dst = (u_char far*)MK_FP_WINDOW(SEND_DATA_BUF,
                                  SBUFBASEADDRESS[s] + offset);

	if (len == 0)
   {
   	WINDOW_RESTORE_BASE;    // Needed whenever we do a call to MK_FP_WINDOW.
  		return 0;
   }

	if ((offset + len) > SSIZE[s])
   {
		size = (u_int)(SSIZE[s] - offset);

  		for (i = 0; i < size; i++)
    	{
	 		WRITE_VALUE(dst, *src++);
         WINDOW_PTR_INC(dst);
	 	}

  		size1 = len - size;
  		dst = (u_char far *)(MK_FP_WINDOW(SEND_DATA_BUF, (SBUFBASEADDRESS[s])));

  		for (i = 0; i < size1; i++)
    	{
	 		WRITE_VALUE(dst, *src++);
         WINDOW_PTR_INC(dst);
	 	}
  }
  else
  {
  	for (i = 0; i < len; i++)
    	{
	 		WRITE_VALUE(dst, *src++);
         WINDOW_PTR_INC(dst);
	 	}
  	}
   WINDOW_RESTORE_BASE;    // Needed whenever we do a call to MK_FP_WINDOW.
	return len;
}