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 Software.Distribution@CS.CMU.EDU
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/param.h>
34 #include <sys/kdb.h>
35 #include <sys/endian.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
db_get_value(db_addr_t addr,int size,bool is_signed)53 db_get_value(db_addr_t addr, int size, bool is_signed)
54 {
55 char data[sizeof(uint64_t)];
56 db_expr_t value;
57 int i;
58
59 if (db_read_bytes(addr, size, data) != 0) {
60 db_printf("*** error reading from address %llx ***\n",
61 (long long)addr);
62 kdb_reenter();
63 }
64
65 value = 0;
66 #if _BYTE_ORDER == _BIG_ENDIAN
67 for (i = 0; i < size; i++)
68 #else /* _LITTLE_ENDIAN */
69 for (i = size - 1; i >= 0; i--)
70 #endif
71 {
72 value = (value << 8) + (data[i] & 0xFF);
73 }
74
75 if (size < 4) {
76 if (is_signed && (value & db_extend[size]) != 0)
77 value |= db_extend[size];
78 }
79 return (value);
80 }
81
82 void
db_put_value(db_addr_t addr,int size,db_expr_t value)83 db_put_value(db_addr_t addr, int size, db_expr_t value)
84 {
85 char data[sizeof(int)];
86 int i;
87
88 #if _BYTE_ORDER == _BIG_ENDIAN
89 for (i = size - 1; i >= 0; i--)
90 #else /* _LITTLE_ENDIAN */
91 for (i = 0; i < size; i++)
92 #endif
93 {
94 data[i] = value & 0xFF;
95 value >>= 8;
96 }
97
98 if (db_write_bytes(addr, size, data) != 0) {
99 db_printf("*** error writing to address %llx ***\n",
100 (long long)addr);
101 kdb_reenter();
102 }
103 }
104