1/*	$NetBSD: sum.c,v 1.4 2008/04/28 20:24:16 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Luke Mewburn of Wasabi Systems.
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/*
33 * Copyright (c) 1999 Ross Harvey.  All rights reserved.
34 *
35 * Redistribution and use in source and binary forms, with or without
36 * modification, are permitted provided that the following conditions
37 * are met:
38 * 1. Redistributions of source code must retain the above copyright
39 *    notice, this list of conditions and the following disclaimer.
40 * 2. Redistributions in binary form must reproduce the above copyright
41 *    notice, this list of conditions and the following disclaimer in the
42 *    documentation and/or other materials provided with the distribution.
43 * 3. All advertising materials mentioning features or use of this software
44 *    must display the following acknowledgement:
45 *      This product includes software developed by Ross Harvey
46 *	for the NetBSD Project.
47 * 4. The name of the author may not be used to endorse or promote products
48 *    derived from this software without specific prior written permission
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
60 */
61
62#if HAVE_NBTOOL_CONFIG_H
63#include "nbtool_config.h"
64#endif
65
66#include <sys/cdefs.h>
67#if !defined(__lint)
68__RCSID("$NetBSD: sum.c,v 1.4 2008/04/28 20:24:16 martin Exp $");
69#endif	/* !__lint */
70
71#include <sys/types.h>
72
73#include <assert.h>
74#include <stdio.h>
75
76#include "installboot.h"
77
78
79uint16_t
80compute_sunsum(const uint16_t *bb16)
81{
82	uint16_t	i, s;
83
84	assert(bb16 != NULL);
85
86	s = 0;
87	for (i = 0; i < 255; ++i)
88		s ^= bb16[i];
89	return (s);
90}
91
92int
93set_sunsum(ib_params *params, uint16_t *bb16, uint16_t sum)
94{
95
96	assert(params != NULL);
97	assert(bb16 != NULL);
98
99#define	SUNSUM_OFFSET	255
100	if (params->flags & IB_VERBOSE) {
101		printf("Old Sun checksum:          0x%04x\n",
102		    be16toh(bb16[SUNSUM_OFFSET]));
103		printf("Recalculated Sun checksum: 0x%04x\n", be16toh(sum));
104	}
105		// XXX: does this need to be big endian?
106	bb16[SUNSUM_OFFSET] = sum;
107	return (1);
108}
109