1 /* Unaligned memory access functionality.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2008 Red Hat, Inc.
3 Written by Ulrich Drepper <drepper@redhat.com>, 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 <byteswap.h>
33 #include <endian.h>
34 #include <limits.h>
35 #include <stdint.h>
36
37
38 /* When loading this file we require the macro MACHINE_ENCODING to be
39 defined to signal the endianness of the architecture which is
40 defined. */
41 #ifndef MACHINE_ENCODING
42 # error "MACHINE_ENCODING needs to be defined"
43 #endif
44 #if MACHINE_ENCODING != __BIG_ENDIAN && MACHINE_ENCODING != __LITTLE_ENDIAN
45 # error "MACHINE_ENCODING must signal either big or little endian"
46 #endif
47
48
49 /* We use simple memory access functions in case the hardware allows it.
50 The caller has to make sure we don't have alias problems. */
51 #if ALLOW_UNALIGNED
52
53 # define read_2ubyte_unaligned(Addr) \
54 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
55 ? bswap_16 (*((const uint16_t *) (Addr))) \
56 : *((const uint16_t *) (Addr)))
57 # define read_2sbyte_unaligned(Addr) \
58 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
59 ? (int16_t) bswap_16 (*((const int16_t *) (Addr))) \
60 : *((const int16_t *) (Addr)))
61
62 # define read_4ubyte_unaligned_noncvt(Addr) \
63 *((const uint32_t *) (Addr))
64 # define read_4ubyte_unaligned(Addr) \
65 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
66 ? bswap_32 (*((const uint32_t *) (Addr))) \
67 : *((const uint32_t *) (Addr)))
68 # define read_4sbyte_unaligned(Addr) \
69 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
70 ? (int32_t) bswap_32 (*((const int32_t *) (Addr))) \
71 : *((const int32_t *) (Addr)))
72
73 # define read_8ubyte_unaligned(Addr) \
74 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
75 ? bswap_64 (*((const uint64_t *) (Addr))) \
76 : *((const uint64_t *) (Addr)))
77 # define read_8sbyte_unaligned(Addr) \
78 (unlikely (MACHINE_ENCODING != __BYTE_ORDER) \
79 ? (int64_t) bswap_64 (*((const int64_t *) (Addr))) \
80 : *((const int64_t *) (Addr)))
81
82 #else
83
84 union unaligned
85 {
86 void *p;
87 uint16_t u2;
88 uint32_t u4;
89 uint64_t u8;
90 int16_t s2;
91 int32_t s4;
92 int64_t s8;
93 } __attribute__ ((packed));
94
95 static inline uint16_t
read_2ubyte_unaligned(const void * p)96 read_2ubyte_unaligned (const void *p)
97 {
98 const union unaligned *up = p;
99 if (MACHINE_ENCODING != __BYTE_ORDER)
100 return bswap_16 (up->u2);
101 return up->u2;
102 }
103 static inline int16_t
read_2sbyte_unaligned(const void * p)104 read_2sbyte_unaligned (const void *p)
105 {
106 const union unaligned *up = p;
107 if (MACHINE_ENCODING != __BYTE_ORDER)
108 return (int16_t) bswap_16 (up->u2);
109 return up->s2;
110 }
111
112 static inline uint32_t
read_4ubyte_unaligned_noncvt(const void * p)113 read_4ubyte_unaligned_noncvt (const void *p)
114 {
115 const union unaligned *up = p;
116 return up->u4;
117 }
118 static inline uint32_t
read_4ubyte_unaligned(const void * p)119 read_4ubyte_unaligned (const void *p)
120 {
121 const union unaligned *up = p;
122 if (MACHINE_ENCODING != __BYTE_ORDER)
123 return bswap_32 (up->u4);
124 return up->u4;
125 }
126 static inline int32_t
read_4sbyte_unaligned(const void * p)127 read_4sbyte_unaligned (const void *p)
128 {
129 const union unaligned *up = p;
130 if (MACHINE_ENCODING != __BYTE_ORDER)
131 return (int32_t) bswap_32 (up->u4);
132 return up->s4;
133 }
134
135 static inline uint64_t
read_8ubyte_unaligned(const void * p)136 read_8ubyte_unaligned (const void *p)
137 {
138 const union unaligned *up = p;
139 if (MACHINE_ENCODING != __BYTE_ORDER)
140 return bswap_64 (up->u8);
141 return up->u8;
142 }
143 static inline int64_t
read_8sbyte_unaligned(const void * p)144 read_8sbyte_unaligned (const void *p)
145 {
146 const union unaligned *up = p;
147 if (MACHINE_ENCODING != __BYTE_ORDER)
148 return (int64_t) bswap_64 (up->u8);
149 return up->s8;
150 }
151
152 #endif /* allow unaligned */
153
154
155 #define read_2ubyte_unaligned_inc(Addr) \
156 ({ uint16_t t_ = read_2ubyte_unaligned (Addr); \
157 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 2); \
158 t_; })
159 #define read_2sbyte_unaligned_inc(Addr) \
160 ({ int16_t t_ = read_2sbyte_unaligned (Addr); \
161 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 2); \
162 t_; })
163
164 #define read_4ubyte_unaligned_inc(Addr) \
165 ({ uint32_t t_ = read_4ubyte_unaligned (Addr); \
166 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 4); \
167 t_; })
168 #define read_4sbyte_unaligned_inc(Addr) \
169 ({ int32_t t_ = read_4sbyte_unaligned (Addr); \
170 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 4); \
171 t_; })
172
173 #define read_8ubyte_unaligned_inc(Addr) \
174 ({ uint64_t t_ = read_8ubyte_unaligned (Addr); \
175 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 8); \
176 t_; })
177 #define read_8sbyte_unaligned_inc(Addr) \
178 ({ int64_t t_ = read_8sbyte_unaligned (Addr); \
179 Addr = (__typeof (Addr)) (((uintptr_t) (Addr)) + 8); \
180 t_; })
181
182 #endif /* memory-access.h */
183