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      1 /*	$NetBSD: cksum.c,v 1.3 2009/03/14 21:04:06 dsl 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "privahdi.h"
     33 
     34 /*
     35  * Disklabel checksum.
     36  */
     37 
     38 int
     39 dkcksum (struct disklabel *dl)
     40 {
     41 	u_short	*start, *end, sum = 0;
     42 
     43 	start = (u_short *)dl;
     44 	end   = (u_short *)&dl->d_partitions[dl->d_npartitions];
     45 	while (start < end)
     46 		sum ^= *start++;
     47 	return (sum);
     48 }
     49 
     50 /*
     51  * AHDI root sector checksum.
     52  */
     53 
     54 u_int16_t
     55 ahdi_cksum (void *buf)
     56 {
     57 	u_int16_t	*p = (u_int16_t *)buf;
     58 	u_int16_t	 csum = 0;
     59 	int		 i;
     60 
     61 	for (i = 0; i < 256; i++)
     62 		csum += *p++;
     63 	return ((0x1234 - csum) & 0xffff);
     64 }
     65