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cksum.c revision 1.1 
      1 /*	$NetBSD: cksum.c,v 1.1 2000/08/07 09:23:40 leo Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Julian Coleman, Waldi Ravens and Leo Weppelman.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include "privahdi.h"
     40 
     41 /*
     42  * Disklabel checksum.
     43  */
     44 
     45 int
     46 dkcksum (dl)
     47 	struct disklabel	*dl;
     48 {
     49 	u_short	*start, *end, sum = 0;
     50 
     51 	start = (u_short *)dl;
     52 	end   = (u_short *)&dl->d_partitions[dl->d_npartitions];
     53 	while (start < end)
     54 		sum ^= *start++;
     55 	return (sum);
     56 }
     57 
     58 /*
     59  * AHDI root sector checksum.
     60  */
     61 
     62 u_int16_t
     63 ahdi_cksum (buf)
     64 	void	*buf;
     65 {
     66 	u_int16_t	*p = (u_int16_t *)buf;
     67 	u_int16_t	 csum = 0;
     68 	int		 i;
     69 
     70 	for (i = 0; i < 256; i++)
     71 		csum += *p++;
     72 	return ((0x1234 - csum) & 0xffff);
     73 }
     74