SDL  2.0
SDL_endian.h
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 
22 /**
23  * \file SDL_endian.h
24  *
25  * Functions for reading and writing endian-specific values
26  */
27 
28 #ifndef SDL_endian_h_
29 #define SDL_endian_h_
30 
31 #include "SDL_stdinc.h"
32 
33 #if defined(_MSC_VER) && (_MSC_VER >= 1400)
34 /* As of Clang 11, '_m_prefetchw' is conflicting with the winnt.h's version,
35  so we define the needed '_m_prefetch' here as a pseudo-header, until the issue is fixed. */
36 #ifdef __clang__
37 #ifndef __PRFCHWINTRIN_H
38 #define __PRFCHWINTRIN_H
39 static __inline__ void __attribute__((__always_inline__, __nodebug__))
40 _m_prefetch(void *__P)
41 {
42  __builtin_prefetch (__P, 0, 3 /* _MM_HINT_T0 */);
43 }
44 #endif /* __PRFCHWINTRIN_H */
45 #endif /* __clang__ */
46 
47 #include <intrin.h>
48 #endif
49 
50 /**
51  * \name The two types of endianness
52  */
53 /* @{ */
54 #define SDL_LIL_ENDIAN 1234
55 #define SDL_BIG_ENDIAN 4321
56 /* @} */
57 
58 #ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
59 #ifdef __linux__
60 #include <endian.h>
61 #define SDL_BYTEORDER __BYTE_ORDER
62 #elif defined(__OpenBSD__)
63 #include <endian.h>
64 #define SDL_BYTEORDER BYTE_ORDER
65 #elif defined(__FreeBSD__) || defined(__NetBSD__)
66 #include <sys/endian.h>
67 #define SDL_BYTEORDER BYTE_ORDER
68 #else
69 #if defined(__hppa__) || \
70  defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
71  (defined(__MIPS__) && defined(__MIPSEB__)) || \
72  defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
73  defined(__sparc__)
74 #define SDL_BYTEORDER SDL_BIG_ENDIAN
75 #else
76 #define SDL_BYTEORDER SDL_LIL_ENDIAN
77 #endif
78 #endif /* __linux__ */
79 #endif /* !SDL_BYTEORDER */
80 
81 
82 #include "begin_code.h"
83 /* Set up for C function definitions, even when using C++ */
84 #ifdef __cplusplus
85 extern "C" {
86 #endif
87 
88 /**
89  * \file SDL_endian.h
90  */
91 
92 /* various modern compilers may have builtin swap */
93 #if defined(__GNUC__) || defined(__clang__)
94 # define HAS_BUILTIN_BSWAP16 (_SDL_HAS_BUILTIN(__builtin_bswap16)) || \
95  (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))
96 # define HAS_BUILTIN_BSWAP32 (_SDL_HAS_BUILTIN(__builtin_bswap32)) || \
97  (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
98 # define HAS_BUILTIN_BSWAP64 (_SDL_HAS_BUILTIN(__builtin_bswap64)) || \
99  (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
100 
101  /* this one is broken */
102 # define HAS_BROKEN_BSWAP (__GNUC__ == 2 && __GNUC_MINOR__ <= 95)
103 #else
104 # define HAS_BUILTIN_BSWAP16 0
105 # define HAS_BUILTIN_BSWAP32 0
106 # define HAS_BUILTIN_BSWAP64 0
107 # define HAS_BROKEN_BSWAP 0
108 #endif
109 
110 #if HAS_BUILTIN_BSWAP16
111 #define SDL_Swap16(x) __builtin_bswap16(x)
112 #elif defined(_MSC_VER) && (_MSC_VER >= 1400)
113 #pragma intrinsic(_byteswap_ushort)
114 #define SDL_Swap16(x) _byteswap_ushort(x)
115 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
118 {
119  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
120  return x;
121 }
122 #elif defined(__x86_64__)
125 {
126  __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
127  return x;
128 }
129 #elif (defined(__powerpc__) || defined(__ppc__))
132 {
133  int result;
134 
135  __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
136  return (Uint16)result;
137 }
138 #elif (defined(__m68k__) && !defined(__mcoldfire__))
141 {
142  __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
143  return x;
144 }
145 #elif defined(__WATCOMC__) && defined(__386__)
146 extern __inline Uint16 SDL_Swap16(Uint16);
147 #pragma aux SDL_Swap16 = \
148  "xchg al, ah" \
149  parm [ax] \
150  modify [ax];
151 #else
154 {
155  return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
156 }
157 #endif
158 
159 #if HAS_BUILTIN_BSWAP32
160 #define SDL_Swap32(x) __builtin_bswap32(x)
161 #elif defined(_MSC_VER) && (_MSC_VER >= 1400)
162 #pragma intrinsic(_byteswap_ulong)
163 #define SDL_Swap32(x) _byteswap_ulong(x)
164 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
167 {
168  __asm__("bswap %0": "=r"(x):"0"(x));
169  return x;
170 }
171 #elif defined(__x86_64__)
174 {
175  __asm__("bswapl %0": "=r"(x):"0"(x));
176  return x;
177 }
178 #elif (defined(__powerpc__) || defined(__ppc__))
181 {
182  Uint32 result;
183 
184  __asm__("rlwimi %0,%2,24,16,23": "=&r"(result): "0" (x>>24), "r"(x));
185  __asm__("rlwimi %0,%2,8,8,15" : "=&r"(result): "0" (result), "r"(x));
186  __asm__("rlwimi %0,%2,24,0,7" : "=&r"(result): "0" (result), "r"(x));
187  return result;
188 }
189 #elif (defined(__m68k__) && !defined(__mcoldfire__))
192 {
193  __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
194  return x;
195 }
196 #elif defined(__WATCOMC__) && defined(__386__)
197 extern __inline Uint32 SDL_Swap32(Uint32);
198 #pragma aux SDL_Swap32 = \
199  "bswap eax" \
200  parm [eax] \
201  modify [eax];
202 #else
205 {
206  return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
207  ((x >> 8) & 0x0000FF00) | (x >> 24)));
208 }
209 #endif
210 
211 #if HAS_BUILTIN_BSWAP64
212 #define SDL_Swap64(x) __builtin_bswap64(x)
213 #elif defined(_MSC_VER) && (_MSC_VER >= 1400)
214 #pragma intrinsic(_byteswap_uint64)
215 #define SDL_Swap64(x) _byteswap_uint64(x)
216 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
219 {
220  union {
221  struct {
222  Uint32 a, b;
223  } s;
224  Uint64 u;
225  } v;
226  v.u = x;
227  __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
228  : "=r"(v.s.a), "=r"(v.s.b)
229  : "0" (v.s.a), "1"(v.s.b));
230  return v.u;
231 }
232 #elif defined(__x86_64__)
235 {
236  __asm__("bswapq %0": "=r"(x):"0"(x));
237  return x;
238 }
239 #elif defined(__WATCOMC__) && defined(__386__)
240 extern __inline Uint64 SDL_Swap64(Uint64);
241 #pragma aux SDL_Swap64 = \
242  "bswap eax" \
243  "bswap edx" \
244  "xchg eax,edx" \
245  parm [eax edx] \
246  modify [eax edx];
247 #else
250 {
251  Uint32 hi, lo;
252 
253  /* Separate into high and low 32-bit values and swap them */
254  lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
255  x >>= 32;
256  hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
257  x = SDL_Swap32(lo);
258  x <<= 32;
259  x |= SDL_Swap32(hi);
260  return (x);
261 }
262 #endif
263 
264 
265 SDL_FORCE_INLINE float
267 {
268  union {
269  float f;
270  Uint32 ui32;
271  } swapper;
272  swapper.f = x;
273  swapper.ui32 = SDL_Swap32(swapper.ui32);
274  return swapper.f;
275 }
276 
277 /* remove extra macros */
278 #undef HAS_BROKEN_BSWAP
279 #undef HAS_BUILTIN_BSWAP16
280 #undef HAS_BUILTIN_BSWAP32
281 #undef HAS_BUILTIN_BSWAP64
282 
283 /**
284  * \name Swap to native
285  * Byteswap item from the specified endianness to the native endianness.
286  */
287 /* @{ */
288 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
289 #define SDL_SwapLE16(X) (X)
290 #define SDL_SwapLE32(X) (X)
291 #define SDL_SwapLE64(X) (X)
292 #define SDL_SwapFloatLE(X) (X)
293 #define SDL_SwapBE16(X) SDL_Swap16(X)
294 #define SDL_SwapBE32(X) SDL_Swap32(X)
295 #define SDL_SwapBE64(X) SDL_Swap64(X)
296 #define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
297 #else
298 #define SDL_SwapLE16(X) SDL_Swap16(X)
299 #define SDL_SwapLE32(X) SDL_Swap32(X)
300 #define SDL_SwapLE64(X) SDL_Swap64(X)
301 #define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
302 #define SDL_SwapBE16(X) (X)
303 #define SDL_SwapBE32(X) (X)
304 #define SDL_SwapBE64(X) (X)
305 #define SDL_SwapFloatBE(X) (X)
306 #endif
307 /* @} *//* Swap to native */
308 
309 /* Ends C function definitions when using C++ */
310 #ifdef __cplusplus
311 }
312 #endif
313 #include "close_code.h"
314 
315 #endif /* SDL_endian_h_ */
316 
317 /* vi: set ts=4 sw=4 expandtab: */
SDL_FORCE_INLINE Uint32 SDL_Swap32(Uint32 x)
Definition: SDL_endian.h:204
SDL_FORCE_INLINE Uint16 SDL_Swap16(Uint16 x)
Definition: SDL_endian.h:153
SDL_FORCE_INLINE float SDL_SwapFloat(float x)
Definition: SDL_endian.h:266
SDL_FORCE_INLINE Uint64 SDL_Swap64(Uint64 x)
Definition: SDL_endian.h:249
uint16_t Uint16
Definition: SDL_stdinc.h:208
#define SDL_static_cast(type, expression)
Definition: SDL_stdinc.h:155
uint64_t Uint64
Definition: SDL_stdinc.h:233
uint32_t Uint32
Definition: SDL_stdinc.h:220
#define __inline__
Definition: begin_code.h:132
#define SDL_FORCE_INLINE
Definition: begin_code.h:143