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 * $FreeBSD: src/sys/ddb/db_access.c,v 1.15 1999/08/28 00:41:04 peter Exp $
27 */
28
29 /*
30 * Author: David B. Golub, Carnegie Mellon University
31 * Date: 7/90
32 */
33 #include <sys/param.h>
34 #include <machine/limits.h>
35
36 #include <ddb/ddb.h>
37 #include <ddb/db_access.h>
38
39 /*
40 * Access unaligned data items on aligned (longword)
41 * boundaries.
42 */
43
44 #if LONG_BIT == 32
45
46 static unsigned db_extend[] = { /* table for sign-extending */
47 0,
48 0xFFFFFF80U,
49 0xFFFF8000U,
50 0xFF800000U
51 };
52
53 #else
54
55 static unsigned long db_extend[] = { /* table for sign-extending */
56 0,
57 0xFFFFFFFFFFFFFF80LU,
58 0xFFFFFFFFFFFF8000LU,
59 0xFFFFFFFFFF800000LU,
60 0xFFFFFFFF80000000LU,
61 0xFFFFFF8000000000LU,
62 0xFFFF800000000000LU,
63 0xFF80000000000000LU
64 };
65
66 #endif
67
68 #ifndef BYTE_MSF
69 #define BYTE_MSF 0
70 #endif
71
72 db_expr_t
db_get_value(db_addr_t addr,int size,boolean_t is_signed)73 db_get_value(db_addr_t addr, int size, boolean_t is_signed)
74 {
75 char data[sizeof(long)];
76 int i;
77 db_expr_t value;
78
79 if (size > sizeof(long))
80 size = sizeof(long);
81
82 db_read_bytes(addr, size, data);
83
84 value = 0;
85 #if BYTE_MSF
86 for (i = 0; i < size; i++)
87 #else /* BYTE_LSF */
88 for (i = size - 1; i >= 0; i--)
89 #endif
90 {
91 value = (value << 8) + (data[i] & 0xFF);
92 }
93
94 if (size < sizeof(long)) {
95 if (is_signed && (value & db_extend[size]) != 0)
96 value |= db_extend[size];
97 }
98 return (value);
99 }
100
101 void
db_put_value(db_addr_t addr,int size,db_expr_t value)102 db_put_value(db_addr_t addr, int size, db_expr_t value)
103 {
104 char data[sizeof(long)];
105 int i;
106
107 if (size > sizeof(long))
108 size = sizeof(long);
109
110 #if BYTE_MSF
111 for (i = size - 1; i >= 0; i--)
112 #else /* BYTE_LSF */
113 for (i = 0; i < size; i++)
114 #endif
115 {
116 data[i] = value & 0xFF;
117 value >>= 8;
118 }
119
120 db_write_bytes(addr, size, data);
121 }
122
123