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 * HISTORY
28 * $Log: db_access.c,v $
29 * Revision 1.1 1992/03/25 21:44:50 pace
30 * Initial revision
31 *
32 * Revision 2.3 91/02/05 17:05:44 mrt
33 * Changed to new Mach copyright
34 * [91/01/31 16:16:22 mrt]
35 *
36 * Revision 2.2 90/08/27 21:48:20 dbg
37 * Fix type declarations.
38 * [90/08/07 dbg]
39 * Created.
40 * [90/07/25 dbg]
41 *
42 */
43 /*
44 * Author: David B. Golub, Carnegie Mellon University
45 * Date: 7/90
46 */
47 #include "sys/param.h"
48 #include "proc.h"
49 #include "machine/db/db_machdep.h" /* type definitions */
50
51 /*
52 * Access unaligned data items on aligned (longword)
53 * boundaries.
54 */
55
56 extern void db_read_bytes(); /* machine-dependent */
57 extern void db_write_bytes(); /* machine-dependent */
58
59 int db_extend[] = { /* table for sign-extending */
60 0,
61 0xFFFFFF80,
62 0xFFFF8000,
63 0xFF800000
64 };
65
66 db_expr_t
db_get_value(addr,size,is_signed)67 db_get_value(addr, size, is_signed)
68 db_addr_t addr;
69 register int size;
70 boolean_t is_signed;
71 {
72 char data[sizeof(int)];
73 register db_expr_t value;
74 register int i;
75
76 db_read_bytes(addr, size, data);
77
78 value = 0;
79 #if BYTE_MSF
80 for (i = 0; i < size; i++)
81 #else /* BYTE_LSF */
82 for (i = size - 1; i >= 0; i--)
83 #endif
84 {
85 value = (value << 8) + (data[i] & 0xFF);
86 }
87
88 if (size < 4) {
89 if (is_signed && (value & db_extend[size]) != 0)
90 value |= db_extend[size];
91 }
92 return (value);
93 }
94
95 void
db_put_value(addr,size,value)96 db_put_value(addr, size, value)
97 db_addr_t addr;
98 register int size;
99 register db_expr_t value;
100 {
101 char data[sizeof(int)];
102 register int i;
103
104 #if BYTE_MSF
105 for (i = size - 1; i >= 0; i--)
106 #else /* BYTE_LSF */
107 for (i = 0; i < size; i++)
108 #endif
109 {
110 data[i] = value & 0xFF;
111 value >>= 8;
112 }
113
114 db_write_bytes(addr, size, data);
115 }
116
117