1/*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28/*
29 *	Author: David B. Golub, Carnegie Mellon University
30 *	Date:	7/90
31 */
32
33#include <sys/param.h>
34#include <sys/kdb.h>
35#include <sys/endian.h>
36
37#include <ddb/ddb.h>
38#include <ddb/db_access.h>
39
40/*
41 * Access unaligned data items on aligned (longword)
42 * boundaries.
43 */
44
45static unsigned db_extend[] = {	/* table for sign-extending */
46	0,
47	0xFFFFFF80U,
48	0xFFFF8000U,
49	0xFF800000U
50};
51
52db_expr_t
53db_get_value(db_addr_t addr, int size, bool is_signed)
54{
55	char		data[sizeof(uint64_t)];
56	db_expr_t	value;
57	int		i;
58
59	if (db_read_bytes(addr, size, data) != 0) {
60		db_printf("*** error reading from address %llx ***\n",
61		    (long long)addr);
62		kdb_reenter();
63	}
64
65	value = 0;
66#if _BYTE_ORDER == _BIG_ENDIAN
67	for (i = 0; i < size; i++)
68#else	/* _LITTLE_ENDIAN */
69	for (i = size - 1; i >= 0; i--)
70#endif
71	{
72	    value = (value << 8) + (data[i] & 0xFF);
73	}
74
75	if (size < 4) {
76	    if (is_signed && (value & db_extend[size]) != 0)
77		value |= db_extend[size];
78	}
79	return (value);
80}
81
82void
83db_put_value(db_addr_t addr, int size, db_expr_t value)
84{
85	char		data[sizeof(int)];
86	int		i;
87
88#if _BYTE_ORDER == _BIG_ENDIAN
89	for (i = size - 1; i >= 0; i--)
90#else	/* _LITTLE_ENDIAN */
91	for (i = 0; i < size; i++)
92#endif
93	{
94	    data[i] = value & 0xFF;
95	    value >>= 8;
96	}
97
98	if (db_write_bytes(addr, size, data) != 0) {
99		db_printf("*** error writing to address %llx ***\n",
100		    (long long)addr);
101		kdb_reenter();
102	}
103}
104