1 /* $OpenBSD: db_access.c,v 1.10 2007/03/15 17:10:22 miod Exp $ */
2 /* $NetBSD: db_access.c,v 1.8 1994/10/09 08:37:35 mycroft Exp $ */
3
4 /*
5 * Mach Operating System
6 * Copyright (c) 1991,1990 Carnegie Mellon University
7 * All Rights Reserved.
8 *
9 * Permission to use, copy, modify and distribute this software and its
10 * documentation is hereby granted, provided that both the copyright
11 * notice and this permission notice appear in all copies of the
12 * software, derivative works or modified versions, and any portions
13 * thereof, and that both notices appear in supporting documentation.
14 *
15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
17 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18 *
19 * Carnegie Mellon requests users of this software to return to
20 *
21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
22 * School of Computer Science
23 * Carnegie Mellon University
24 * Pittsburgh PA 15213-3890
25 *
26 * any improvements or extensions that they make and grant Carnegie the
27 * the rights to redistribute these changes.
28 *
29 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 #include <sys/param.h>
34 #include <sys/proc.h>
35
36 #include <uvm/uvm_extern.h>
37
38 #include <machine/db_machdep.h> /* type definitions */
39 #include <machine/endian.h>
40
41 #include <ddb/db_access.h>
42
43 /*
44 * Access unaligned data items on aligned (longword)
45 * boundaries.
46 */
47 db_expr_t
48 db_get_value(db_addr_t addr, size_t size, boolean_t is_signed)
49 {
50 char data[sizeof(db_expr_t)];
51 db_expr_t value, extend;
52 int i;
53
54 #ifdef DIAGNOSTIC
55 if (size > sizeof data)
56 size = sizeof data;
57 #endif
58
59 db_read_bytes(addr, size, data);
60
61 value = 0;
62 extend = (~(db_expr_t)0) << (size * 8 - 1);
63 #if BYTE_ORDER == LITTLE_ENDIAN
64 for (i = size - 1; i >= 0; i--)
65 #else /* BYTE_ORDER == BIG_ENDIAN */
66 for (i = 0; i < size; i++)
67 #endif /* BYTE_ORDER */
68 value = (value << 8) + (data[i] & 0xFF);
69
70 if (size < sizeof(db_expr_t) && is_signed && (value & extend))
71 value |= extend;
72 return (value);
73 }
74
75 void
76 db_put_value(db_addr_t addr, size_t size, db_expr_t value)
77 {
78 char data[sizeof(db_expr_t)];
79 int i;
80
81 #ifdef DIAGNOSTIC
82 if (size > sizeof data)
83 size = sizeof data;
84 #endif
85
86 #if BYTE_ORDER == LITTLE_ENDIAN
87 for (i = 0; i < size; i++)
88 #else /* BYTE_ORDER == BIG_ENDIAN */
89 for (i = size - 1; i >= 0; i--)
90 #endif /* BYTE_ORDER */
91 {
92 data[i] = value & 0xff;
93 value >>= 8;
94 }
95
96 db_write_bytes(addr, size, data);
97 }