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[apple/xnu.git] / libkern / libkern / arm / OSByteOrder.h
1 /*
2 * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
3 */
4
5 #ifndef _OS_OSBYTEORDERARM_H
6 #define _OS_OSBYTEORDERARM_H
7
8 #include <stdint.h>
9 #include <arm/arch.h> /* for _ARM_ARCH_6 */
10
11 /* Generic byte swapping functions. */
12
13 __DARWIN_OS_INLINE
14 uint16_t
15 _OSSwapInt16(
16 uint16_t _data
17 )
18 {
19 /* Reduces to 'rev16' with clang */
20 return (uint16_t)(_data << 8 | _data >> 8);
21 }
22
23 __DARWIN_OS_INLINE
24 uint32_t
25 _OSSwapInt32(
26 uint32_t _data
27 )
28 {
29 #if defined(__llvm__)
30 _data = __builtin_bswap32(_data);
31 #else
32 /* This actually generates the best code */
33 _data = (((_data ^ (_data >> 16 | (_data << 16))) & 0xFF00FFFF) >> 8) ^ (_data >> 8 | _data << 24);
34 #endif
35
36 return _data;
37 }
38
39 __DARWIN_OS_INLINE
40 uint64_t
41 _OSSwapInt64(
42 uint64_t _data
43 )
44 {
45 #if defined(__llvm__)
46 return __builtin_bswap64(_data);
47 #else
48 union {
49 uint64_t _ull;
50 uint32_t _ul[2];
51 } _u;
52
53 /* This actually generates the best code */
54 _u._ul[0] = (uint32_t)(_data >> 32);
55 _u._ul[1] = (uint32_t)(_data & 0xffffffff);
56 _u._ul[0] = _OSSwapInt32(_u._ul[0]);
57 _u._ul[1] = _OSSwapInt32(_u._ul[1]);
58 return _u._ull;
59 #endif
60 }
61
62 /* Functions for byte reversed loads. */
63
64 struct _OSUnalignedU16 {
65 volatile uint16_t __val;
66 } __attribute__((__packed__));
67
68 struct _OSUnalignedU32 {
69 volatile uint32_t __val;
70 } __attribute__((__packed__));
71
72 struct _OSUnalignedU64 {
73 volatile uint64_t __val;
74 } __attribute__((__packed__));
75
76 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
77 __DARWIN_OS_INLINE
78 uint16_t
79 _OSReadSwapInt16(
80 const volatile void * _base,
81 uintptr_t _offset
82 )
83 {
84 return _OSSwapInt16(((struct _OSUnalignedU16 *)((uintptr_t)_base + _offset))->__val);
85 }
86 #else
87 __DARWIN_OS_INLINE
88 uint16_t
89 OSReadSwapInt16(
90 const volatile void * _base,
91 uintptr_t _offset
92 )
93 {
94 return _OSSwapInt16(((struct _OSUnalignedU16 *)((uintptr_t)_base + _offset))->__val);
95 }
96 #endif
97
98 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
99 __DARWIN_OS_INLINE
100 uint32_t
101 _OSReadSwapInt32(
102 const volatile void * _base,
103 uintptr_t _offset
104 )
105 {
106 return _OSSwapInt32(((struct _OSUnalignedU32 *)((uintptr_t)_base + _offset))->__val);
107 }
108 #else
109 __DARWIN_OS_INLINE
110 uint32_t
111 OSReadSwapInt32(
112 const volatile void * _base,
113 uintptr_t _offset
114 )
115 {
116 return _OSSwapInt32(((struct _OSUnalignedU32 *)((uintptr_t)_base + _offset))->__val);
117 }
118 #endif
119
120 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
121 __DARWIN_OS_INLINE
122 uint64_t
123 _OSReadSwapInt64(
124 const volatile void * _base,
125 uintptr_t _offset
126 )
127 {
128 return _OSSwapInt64(((struct _OSUnalignedU64 *)((uintptr_t)_base + _offset))->__val);
129 }
130 #else
131 __DARWIN_OS_INLINE
132 uint64_t
133 OSReadSwapInt64(
134 const volatile void * _base,
135 uintptr_t _offset
136 )
137 {
138 return _OSSwapInt64(((struct _OSUnalignedU64 *)((uintptr_t)_base + _offset))->__val);
139 }
140 #endif
141
142 /* Functions for byte reversed stores. */
143
144 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
145 __DARWIN_OS_INLINE
146 void
147 _OSWriteSwapInt16(
148 volatile void * _base,
149 uintptr_t _offset,
150 uint16_t _data
151 )
152 {
153 ((struct _OSUnalignedU16 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt16(_data);
154 }
155 #else
156 __DARWIN_OS_INLINE
157 void
158 OSWriteSwapInt16(
159 volatile void * _base,
160 uintptr_t _offset,
161 uint16_t _data
162 )
163 {
164 ((struct _OSUnalignedU16 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt16(_data);
165 }
166 #endif
167
168 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
169 __DARWIN_OS_INLINE
170 void
171 _OSWriteSwapInt32(
172 volatile void * _base,
173 uintptr_t _offset,
174 uint32_t _data
175 )
176 {
177 ((struct _OSUnalignedU32 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt32(_data);
178 }
179 #else
180 __DARWIN_OS_INLINE
181 void
182 OSWriteSwapInt32(
183 volatile void * _base,
184 uintptr_t _offset,
185 uint32_t _data
186 )
187 {
188 ((struct _OSUnalignedU32 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt32(_data);
189 }
190 #endif
191
192 #if defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE)
193 __DARWIN_OS_INLINE
194 void
195 _OSWriteSwapInt64(
196 volatile void * _base,
197 uintptr_t _offset,
198 uint64_t _data
199 )
200 {
201 ((struct _OSUnalignedU64 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt64(_data);
202 }
203 #else
204 __DARWIN_OS_INLINE
205 void
206 OSWriteSwapInt64(
207 volatile void * _base,
208 uintptr_t _offset,
209 uint64_t _data
210 )
211 {
212 ((struct _OSUnalignedU64 *)((uintptr_t)_base + _offset))->__val = _OSSwapInt64(_data);
213 }
214 #endif
215
216 #endif /* ! _OS_OSBYTEORDERARM_H */
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