xref: /netbsd-src/sys/arch/atari/stand/ahdilabel/cksum.c (revision 8e6f7afb5bba2c07fd084c08249718961dfbc1d1)
1 /*	$NetBSD: cksum.c,v 1.1.1.1 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