Contiki 2.6
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00001 /* 00002 * Copyright (c) 2007, Swedish Institute of Computer Science. 00003 * All rights reserved. 00004 * 00005 * Redistribution and use in source and binary forms, with or without 00006 * modification, are permitted provided that the following conditions 00007 * are met: 00008 * 1. Redistributions of source code must retain the above copyright 00009 * notice, this list of conditions and the following disclaimer. 00010 * 2. Redistributions in binary form must reproduce the above copyright 00011 * notice, this list of conditions and the following disclaimer in the 00012 * documentation and/or other materials provided with the distribution. 00013 * 3. Neither the name of the Institute nor the names of its contributors 00014 * may be used to endorse or promote products derived from this software 00015 * without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 00018 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00019 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00020 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 00021 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00022 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00023 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00024 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00025 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00026 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00027 * SUCH DAMAGE. 00028 * 00029 * This file is part of the Contiki operating system. 00030 * 00031 * $Id: uip-ipchksum.c,v 1.4 2007/04/04 11:53:07 bg- Exp $ 00032 */ 00033 00034 /** 00035 * \file 00036 * uIP checksum calculation for MSP430 00037 */ 00038 00039 #include "net/uip.h" 00040 00041 #define asmv(arg) __asm__ __volatile__(arg) 00042 /*---------------------------------------------------------------------------*/ 00043 #ifdef UIP_ARCH_IPCHKSUM 00044 #ifdef __IAR_SYSTEMS_ICC__ 00045 uint16_t 00046 uip_ipchksum(void) 00047 { 00048 return 0; 00049 } 00050 #else 00051 uint16_t 00052 uip_ipchksum(void) 00053 { 00054 /* Assumes proper alignement of uip_buf. */ 00055 uint16_t *p = (uint16_t *)&uip_buf[UIP_LLH_LEN]; 00056 register uint16_t sum; 00057 00058 sum = p[0]; 00059 asmv("add %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[1])); 00060 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[2])); 00061 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[3])); 00062 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[4])); 00063 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[5])); 00064 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[6])); 00065 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[7])); 00066 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[8])); 00067 asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[9])); 00068 00069 /* Finally, add the remaining carry bit. */ 00070 asmv("addc #0, %[sum]": [sum] "+r" (sum)); 00071 00072 /* Return sum in network byte order. */ 00073 return (sum == 0) ? 0xffff : sum; 00074 } 00075 #endif 00076 #endif 00077 /*---------------------------------------------------------------------------*/