FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_access.c
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 /*
27 * Author: David B. Golub, Carnegie Mellon University
28 * Date: 7/90
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD: releng/6.0/sys/ddb/db_access.c 139747 2005-01-06 01:34:41Z imp $");
33
34 #include <sys/param.h>
35 #include <sys/kdb.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
45 static unsigned db_extend[] = { /* table for sign-extending */
46 0,
47 0xFFFFFF80U,
48 0xFFFF8000U,
49 0xFF800000U
50 };
51
52 db_expr_t
53 db_get_value(addr, size, is_signed)
54 db_addr_t addr;
55 register int size;
56 boolean_t is_signed;
57 {
58 char data[sizeof(u_int64_t)];
59 register db_expr_t value;
60 register int i;
61
62 if (db_read_bytes(addr, size, data) != 0) {
63 db_printf("*** error reading from address %llx ***\n",
64 (long long)addr);
65 kdb_reenter();
66 }
67
68 value = 0;
69 #if BYTE_MSF
70 for (i = 0; i < size; i++)
71 #else /* BYTE_LSF */
72 for (i = size - 1; i >= 0; i--)
73 #endif
74 {
75 value = (value << 8) + (data[i] & 0xFF);
76 }
77
78 if (size < 4) {
79 if (is_signed && (value & db_extend[size]) != 0)
80 value |= db_extend[size];
81 }
82 return (value);
83 }
84
85 void
86 db_put_value(addr, size, value)
87 db_addr_t addr;
88 register int size;
89 register db_expr_t value;
90 {
91 char data[sizeof(int)];
92 register int i;
93
94 #if BYTE_MSF
95 for (i = size - 1; i >= 0; i--)
96 #else /* BYTE_LSF */
97 for (i = 0; i < size; i++)
98 #endif
99 {
100 data[i] = value & 0xFF;
101 value >>= 8;
102 }
103
104 if (db_write_bytes(addr, size, data) != 0) {
105 db_printf("*** error writing to address %llx ***\n",
106 (long long)addr);
107 kdb_reenter();
108 }
109 }
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