1 /* Unaligned memory access functionality.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2008 Red Hat, Inc.
3 Written by Ulrich Drepper <[email protected]>, 2001.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifndef _MEMORY_ACCESS_H
30 #define _MEMORY_ACCESS_H 1
31
32 #include <limits.h>
33 #include <stdint.h>
34
35 #include <system.h>
36
37 /* When loading this file we require the macro MACHINE_ENCODING to be
38 defined to signal the endianness of the architecture which is
39 defined. */
40 #ifndef MACHINE_ENCODING
41 # error "MACHINE_ENCODING needs to be defined"
42 #endif
43 #if MACHINE_ENCODING != BIG_ENDIAN && MACHINE_ENCODING != LITTLE_ENDIAN
44 # error "MACHINE_ENCODING must signal either big or little endian"
45 #endif
46
47
48 /* We use simple memory access functions in case the hardware allows it.
49 The caller has to make sure we don't have alias problems. */
50 #if ALLOW_UNALIGNED
51
52 # define read_2ubyte_unaligned(Addr) \
53 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
54 ? bswap_16 (*((const uint16_t *) (Addr))) \
55 : *((const uint16_t *) (Addr)))
56 # define read_2sbyte_unaligned(Addr) \
57 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
58 ? (int16_t) bswap_16 (*((const int16_t *) (Addr))) \
59 : *((const int16_t *) (Addr)))
60
61 # define read_4ubyte_unaligned_noncvt(Addr) \
62 *((const uint32_t *) (Addr))
63 # define read_4ubyte_unaligned(Addr) \
64 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
65 ? bswap_32 (*((const uint32_t *) (Addr))) \
66 : *((const uint32_t *) (Addr)))
67 # define read_4sbyte_unaligned(Addr) \
68 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
69 ? (int32_t) bswap_32 (*((const int32_t *) (Addr))) \
70 : *((const int32_t *) (Addr)))
71
72 # define read_8ubyte_unaligned(Addr) \
73 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
74 ? bswap_64 (*((const uint64_t *) (Addr))) \
75 : *((const uint64_t *) (Addr)))
76 # define read_8sbyte_unaligned(Addr) \
77 (unlikely (MACHINE_ENCODING != BYTE_ORDER) \
78 ? (int64_t) bswap_64 (*((const int64_t *) (Addr))) \
79 : *((const int64_t *) (Addr)))
80
81 #else
82
83 union unaligned
84 {
85 void *p;
86 uint16_t u2;
87 uint32_t u4;
88 uint64_t u8;
89 int16_t s2;
90 int32_t s4;
91 int64_t s8;
92 } attribute_packed;
93
94 static inline uint16_t
read_2ubyte_unaligned(const void * p)95 read_2ubyte_unaligned (const void *p)
96 {
97 const union unaligned *up = p;
98 if (MACHINE_ENCODING != BYTE_ORDER)
99 return bswap_16 (up->u2);
100 return up->u2;
101 }
102 static inline int16_t
read_2sbyte_unaligned(const void * p)103 read_2sbyte_unaligned (const void *p)
104 {
105 const union unaligned *up = p;
106 if (MACHINE_ENCODING != BYTE_ORDER)
107 return (int16_t) bswap_16 (up->u2);
108 return up->s2;
109 }
110
111 static inline uint32_t
read_4ubyte_unaligned_noncvt(const void * p)112 read_4ubyte_unaligned_noncvt (const void *p)
113 {
114 const union unaligned *up = p;
115 return up->u4;
116 }
117 static inline uint32_t
read_4ubyte_unaligned(const void * p)118 read_4ubyte_unaligned (const void *p)
119 {
120 const union unaligned *up = p;
121 if (MACHINE_ENCODING != BYTE_ORDER)
122 return bswap_32 (up->u4);
123 return up->u4;
124 }
125 static inline int32_t
read_4sbyte_unaligned(const void * p)126 read_4sbyte_unaligned (const void *p)
127 {
128 const union unaligned *up = p;
129 if (MACHINE_ENCODING != BYTE_ORDER)
130 return (int32_t) bswap_32 (up->u4);
131 return up->s4;
132 }
133
134 static inline uint64_t
read_8ubyte_unaligned(const void * p)135 read_8ubyte_unaligned (const void *p)
136 {
137 const union unaligned *up = p;
138 if (MACHINE_ENCODING != BYTE_ORDER)
139 return bswap_64 (up->u8);
140 return up->u8;
141 }
142 static inline int64_t
read_8sbyte_unaligned(const void * p)143 read_8sbyte_unaligned (const void *p)
144 {
145 const union unaligned *up = p;
146 if (MACHINE_ENCODING != BYTE_ORDER)
147 return (int64_t) bswap_64 (up->u8);
148 return up->s8;
149 }
150
151 #endif /* allow unaligned */
152
153
154 #define read_2ubyte_unaligned_inc(Addr) \
155 ({ uint16_t t_ = read_2ubyte_unaligned (Addr); \
156 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 2); \
157 t_; })
158 #define read_2sbyte_unaligned_inc(Addr) \
159 ({ int16_t t_ = read_2sbyte_unaligned (Addr); \
160 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 2); \
161 t_; })
162
163 #define read_4ubyte_unaligned_inc(Addr) \
164 ({ uint32_t t_ = read_4ubyte_unaligned (Addr); \
165 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 4); \
166 t_; })
167 #define read_4sbyte_unaligned_inc(Addr) \
168 ({ int32_t t_ = read_4sbyte_unaligned (Addr); \
169 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 4); \
170 t_; })
171
172 #define read_8ubyte_unaligned_inc(Addr) \
173 ({ uint64_t t_ = read_8ubyte_unaligned (Addr); \
174 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 8); \
175 t_; })
176 #define read_8sbyte_unaligned_inc(Addr) \
177 ({ int64_t t_ = read_8sbyte_unaligned (Addr); \
178 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 8); \
179 t_; })
180
181 #endif /* memory-access.h */
182