1/*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 *
26 * $Id: db_access.c,v 1.5 1994/08/13 03:49:13 wollman Exp $
27 */
28
29/*
30 * Author: David B. Golub, Carnegie Mellon University
31 * Date: 7/90
32 */
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/proc.h>
36#include <ddb/ddb.h>
37
38/*
39 * Access unaligned data items on aligned (longword)
40 * boundaries.
41 */
42
43unsigned db_extend[] = { /* table for sign-extending */
44 0,
45 0xFFFFFF80U,
46 0xFFFF8000U,
47 0xFF800000U
48};
49
50db_expr_t
51db_get_value(addr, size, is_signed)
52 db_addr_t addr;
53 register int size;
54 boolean_t is_signed;
55{
56 char data[sizeof(int)];
57 register db_expr_t value;
58 register int i;
59
60 db_read_bytes(addr, size, data);
61
62 value = 0;
63#if BYTE_MSF
64 for (i = 0; i < size; i++)
65#else /* BYTE_LSF */
66 for (i = size - 1; i >= 0; i--)
67#endif
68 {
69 value = (value << 8) + (data[i] & 0xFF);
70 }
71
72 if (size < 4) {
73 if (is_signed && (value & db_extend[size]) != 0)
74 value |= db_extend[size];
75 }
76 return (value);
77}
78
79void
80db_put_value(addr, size, value)
81 db_addr_t addr;
82 register int size;
83 register db_expr_t value;
84{
85 char data[sizeof(int)];
86 register int i;
87
88#if BYTE_MSF
89 for (i = size - 1; i >= 0; i--)
90#else /* BYTE_LSF */
91 for (i = 0; i < size; i++)
92#endif
93 {
94 data[i] = value & 0xFF;
95 value >>= 8;
96 }
97
98 db_write_bytes(addr, size, data);
99}
100