N-sim
Emulation and simulation of
Wireless Sensor Networks



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/home/brennan/n-sim/OrbisQuartus/server/l4/patches/lwip-ore/lwip_chksum.c

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00001 /*
00002  * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
00003  * All rights reserved. 
00004  * 
00005  * Redistribution and use in source and binary forms, with or without modification, 
00006  * are permitted provided that the following conditions are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright notice,
00009  *    this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright notice,
00011  *    this list of conditions and the following disclaimer in the documentation
00012  *    and/or other materials provided with the distribution.
00013  * 3. The name of the author may not be used to endorse or promote products
00014  *    derived from this software without specific prior written permission. 
00015  *
00016  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
00017  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
00018  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
00019  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
00020  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
00021  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
00024  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
00025  * OF SUCH DAMAGE.
00026  *
00027  * This file is part of the lwIP TCP/IP stack.
00028  * 
00029  * Author: Adam Dunkels <adam@sics.se>
00030  *
00031  */
00032 
00033 #include "lwip/debug.h"
00034 
00035 #include "lwip/arch.h"
00036 
00037 #include "lwip/def.h"
00038 #include "lwip/inet.h"
00039 
00040 
00041 /*-----------------------------------------------------------------------------------*/
00042 /* lwip_chksum:
00043  *
00044  * Sums up all 16 bit words in a memory portion. Also includes any odd byte.
00045  * This function is used by the other checksum functions.
00046  *
00047  */
00048 /*-----------------------------------------------------------------------------------*/
00049 #if 0
00050 u16_t
00051 lwip_chksum(void *dataptr, int len)
00052 {
00053   u32_t acc;
00054     
00055   for(acc = 0; len > 1; len -= 2) {
00056     acc += *((u16_t *)dataptr)++;
00057   }
00058 
00059   /* add up any odd byte */
00060   if (len == 1) {
00061     acc += htons((u16_t)((*(u8_t *)dataptr) & 0xff) << 8);
00062     LWIP_DEBUGF(INET_DEBUG, ("inet: chksum: odd byte %d\n", *(u8_t *)dataptr));
00063   }
00064   acc = (acc >> 16) + (acc & 0xffffUL);
00065 
00066   if (acc & 0xffff0000 != 0) {
00067     acc = (acc >> 16) + (acc & 0xffffUL);
00068   }
00069 
00070   return (u16_t)acc;
00071 }
00072 /*-----------------------------------------------------------------------------------*/
00073 #endif


© 2007, Los Alamos National Security, LLC.