1 /*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or [email protected]
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28 /*
29 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 #include <sys/cdefs.h>
34 #include <sys/param.h>
35 #include <sys/kdb.h>
36 #include <sys/endian.h>
37
38 #include <ddb/ddb.h>
39 #include <ddb/db_access.h>
40
41 /*
42 * Access unaligned data items on aligned (longword)
43 * boundaries.
44 */
45
46 static unsigned db_extend[] = { /* table for sign-extending */
47 0,
48 0xFFFFFF80U,
49 0xFFFF8000U,
50 0xFF800000U
51 };
52
53 db_expr_t
db_get_value(db_addr_t addr,int size,bool is_signed)54 db_get_value(db_addr_t addr, int size, bool is_signed)
55 {
56 char data[sizeof(uint64_t)];
57 db_expr_t value;
58 int i;
59
60 if (db_read_bytes(addr, size, data) != 0) {
61 db_printf("*** error reading from address %llx ***\n",
62 (long long)addr);
63 kdb_reenter();
64 }
65
66 value = 0;
67 #if _BYTE_ORDER == _BIG_ENDIAN
68 for (i = 0; i < size; i++)
69 #else /* _LITTLE_ENDIAN */
70 for (i = size - 1; i >= 0; i--)
71 #endif
72 {
73 value = (value << 8) + (data[i] & 0xFF);
74 }
75
76 if (size < 4) {
77 if (is_signed && (value & db_extend[size]) != 0)
78 value |= db_extend[size];
79 }
80 return (value);
81 }
82
83 void
db_put_value(db_addr_t addr,int size,db_expr_t value)84 db_put_value(db_addr_t addr, int size, db_expr_t value)
85 {
86 char data[sizeof(int)];
87 int i;
88
89 #if _BYTE_ORDER == _BIG_ENDIAN
90 for (i = size - 1; i >= 0; i--)
91 #else /* _LITTLE_ENDIAN */
92 for (i = 0; i < size; i++)
93 #endif
94 {
95 data[i] = value & 0xFF;
96 value >>= 8;
97 }
98
99 if (db_write_bytes(addr, size, data) != 0) {
100 db_printf("*** error writing to address %llx ***\n",
101 (long long)addr);
102 kdb_reenter();
103 }
104 }
105