/* $Header: /usr/cvsroot/target/src/wrn/wm/demo/lib/cksum.c,v 1.3 2003/01/15 14:04:31 josh Exp $ *//* * Copyright (C) 1999-2005 Wind River Systems, Inc. * All rights reserved.  Provided under license only. * Distribution or other use of this software is only * permitted pursuant to the terms of a license agreement * from Wind River Systems (and is otherwise prohibited). * Refer to that license agreement for terms of use. *//**************************************************************************** *  Copyright 1993-1997 Epilogue Technology Corporation. *  Copyright 1998 Integrated Systems, Inc. *  All rights reserved. ****************************************************************************//* * $Log: cksum.c,v $ * Revision 1.3  2003/01/15 14:04:31  josh * directory structure shifting * * Revision 1.2  2001/11/08 15:56:20  tneale * Updated for newest file layout * * Revision 1.1.1.1  2001/11/05 17:48:41  tneale * Tornado shuffle * * Revision 1.3  2001/01/19 22:23:40  paul * Update copyright. * * Revision 1.2  2000/03/17 00:12:37  meister * Update copyright message * * Revision 1.1  1998/07/15 20:58:21  sra * Initial version. * *//* [clearcase]modification history-------------------01a,19apr05,job  update copyright notices*//* * Checksum routine for Snark demos. * You can almost certainly do better than this in assembly language. */#include <wrn/wm/common/config.h>#include <wrn/wm/common/glue.h>#include <wrn/wm/demo/snarklib.h>#ifndef INSTALL_SNARK_GLUE_CKSUM_ALIGNMENT_KLUDGE#define INSTALL_SNARK_GLUE_CKSUM_ALIGNMENT_KLUDGE defined(__sparc__)#endif#if INSTALL_ATTACHE/* * This code is borrowed from RFC 1071. Note that our checksum function * takes the number of words as an argument, rather than the number of * bytes. Also, we let the caller perform the one's complement change. */bits16_t glue_cksum(bits16_t *addr, unsigned count){  register bits32_t sum = 0;  #if INSTALL_SNARK_GLUE_CKSUM_ALIGNMENT_KLUDGE  /*   * Kludge around alignment restrictions.   */  if (count > 0 && (((unsigned long) addr) & 1) != 0) {    bits8_t *a = (bits8_t *) addr;    sum = glue_cksum((bits16_t *) (a+1), count - 1);    sum = ((sum << 8) & 0xFF00) | ((sum >> 8) & 0x00FF);    sum += ((a[0] << 8) + a[count * 2 - 1]);    count = 0;  }#endif  while (count-- > 0)    sum += *addr++;  sum  = (sum >> 16) + (sum & 0xFFFF);	/* This can only wrap twice */  return (sum >> 16) + (sum & 0xFFFF);}#endif /* INSTALL_ATTACHE */