1 /* $OpenBSD: db_access.c,v 1.16 2019/11/07 13:16:25 mpi 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/endian.h>
35
36 #include <machine/db_machdep.h> /* type definitions */
37
38 #include <ddb/db_access.h>
39
40 /*
41 * Access unaligned data items on aligned (longword)
42 * boundaries.
43 */
44 db_expr_t
db_get_value(vaddr_t addr,size_t size,int is_signed)45 db_get_value(vaddr_t addr, size_t size, int is_signed)
46 {
47 char data[sizeof(db_expr_t)];
48 db_expr_t value, extend;
49 int i;
50
51 #ifdef DIAGNOSTIC
52 if (size > sizeof data)
53 size = sizeof data;
54 #endif
55
56 db_read_bytes(addr, size, data);
57
58 value = 0;
59 extend = (~(db_expr_t)0) << (size * 8 - 1);
60 #if BYTE_ORDER == LITTLE_ENDIAN
61 for (i = size - 1; i >= 0; i--)
62 #else /* BYTE_ORDER == BIG_ENDIAN */
63 for (i = 0; i < size; i++)
64 #endif /* BYTE_ORDER */
65 value = (value << 8) + (data[i] & 0xFF);
66
67 if (size < sizeof(db_expr_t) && is_signed && (value & extend))
68 value |= extend;
69 return (value);
70 }
71
72 void
db_put_value(vaddr_t addr,size_t size,db_expr_t value)73 db_put_value(vaddr_t addr, size_t size, db_expr_t value)
74 {
75 char data[sizeof(db_expr_t)];
76 int i;
77
78 #ifdef DIAGNOSTIC
79 if (size > sizeof data)
80 size = sizeof data;
81 #endif
82
83 #if BYTE_ORDER == LITTLE_ENDIAN
84 for (i = 0; i < size; i++)
85 #else /* BYTE_ORDER == BIG_ENDIAN */
86 for (i = size - 1; i >= 0; i--)
87 #endif /* BYTE_ORDER */
88 {
89 data[i] = value & 0xff;
90 value >>= 8;
91 }
92
93 db_write_bytes(addr, size, data);
94 }
95