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15637ed4 RG |
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 "param.h" | |
48 | #include "proc.h" | |
49 | #include <machine/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 | |
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 | |
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 |