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/home/brennan/n-sim/OrbisQuartus/server/l4/patches/lwip-ore/lwip_chksum.cGo to the documentation of this file.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 |