1 /* $OpenBSD: db_access.c,v 1.8 2001/11/06 19:53:18 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
db_get_value(addr,size,is_signed)48 db_get_value(addr, size, is_signed)
49 db_addr_t addr;
50 size_t size;
51 boolean_t is_signed;
52 {
53 char data[sizeof(db_expr_t)];
54 db_expr_t value, extend;
55 int i;
56
57 db_read_bytes(addr, size, data);
58
59 value = 0;
60 extend = (~(db_expr_t)0) << (size * 8 - 1);
61 #if BYTE_ORDER == LITTLE_ENDIAN
62 for (i = size - 1; i >= 0; i--)
63 #else /* BYTE_ORDER == BIG_ENDIAN */
64 for (i = 0; i < size; i++)
65 #endif /* BYTE_ORDER */
66 value = (value << 8) + (data[i] & 0xFF);
67
68 if (size < sizeof(db_expr_t) && is_signed && (value & extend))
69 value |= extend;
70 return (value);
71 }
72
73 void
db_put_value(addr,size,value)74 db_put_value(addr, size, value)
75 db_addr_t addr;
76 size_t size;
77 db_expr_t value;
78 {
79 char data[sizeof(db_expr_t)];
80 int i;
81
82 #if BYTE_ORDER == LITTLE_ENDIAN
83 for (i = 0; i < size; i++)
84 #else /* BYTE_ORDER == BIG_ENDIAN */
85 for (i = size - 1; i >= 0; i--)
86 #endif /* BYTE_ORDER */
87 {
88 data[i] = value & 0xff;
89 value >>= 8;
90 }
91
92 db_write_bytes(addr, size, data);
93 }
94