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 #ifdef _MSC_VER
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 
37 #ifdef __clang__
38 #ifndef __PRFCHWINTRIN_H
39 #define __PRFCHWINTRIN_H
40 
41 static __inline__ void __attribute__((__always_inline__, __nodebug__))
42 _m_prefetch(void *__P)
43 {
44  __builtin_prefetch (__P, 0, 3 /* _MM_HINT_T0 */);
45 }
46 
47 #endif /* __PRFCHWINTRIN_H */
48 #endif /* __clang__ */
49 
50 #include <intrin.h>
51 #endif
52 
53 /**
54  * \name The two types of endianness
55  */
56 /* @{ */
57 #define SDL_LIL_ENDIAN 1234
58 #define SDL_BIG_ENDIAN 4321
59 /* @} */
60 
61 #ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
62 #ifdef __linux__
63 #include <endian.h>
64 #define SDL_BYTEORDER __BYTE_ORDER
65 #elif defined(__OpenBSD__)
66 #include <endian.h>
67 #define SDL_BYTEORDER BYTE_ORDER
68 #elif defined(__FreeBSD__) || defined(__NetBSD__)
69 #include <sys/endian.h>
70 #define SDL_BYTEORDER BYTE_ORDER
71 #else
72 #if defined(__hppa__) || \
73  defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
74  (defined(__MIPS__) && defined(__MIPSEB__)) || \
75  defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
76  defined(__sparc__)
77 #define SDL_BYTEORDER SDL_BIG_ENDIAN
78 #else
79 #define SDL_BYTEORDER SDL_LIL_ENDIAN
80 #endif
81 #endif /* __linux__ */
82 #endif /* !SDL_BYTEORDER */
83 
84 
85 #include "begin_code.h"
86 /* Set up for C function definitions, even when using C++ */
87 #ifdef __cplusplus
88 extern "C" {
89 #endif
90 
91 /**
92  * \file SDL_endian.h
93  */
94 #if (defined(__clang__) && (__clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 2))) || \
95  (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
96 #define SDL_Swap16(x) __builtin_bswap16(x)
97 #elif defined(__GNUC__) && defined(__i386__) && \
98  !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
101 {
102  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
103  return x;
104 }
105 #elif defined(__GNUC__) && defined(__x86_64__)
108 {
109  __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
110  return x;
111 }
112 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
115 {
116  int result;
117 
118  __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
119  return (Uint16)result;
120 }
121 #elif defined(__GNUC__) && defined(__aarch64__)
124 {
125  __asm__("rev16 %w1, %w0" : "=r"(x) : "r"(x));
126  return x;
127 }
128 #elif defined(__GNUC__) && (defined(__m68k__) && !defined(__mcoldfire__))
131 {
132  __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
133  return x;
134 }
135 #elif defined(_MSC_VER)
136 #pragma intrinsic(_byteswap_ushort)
137 #define SDL_Swap16(x) _byteswap_ushort(x)
138 #elif defined(__WATCOMC__) && defined(__386__)
139 extern _inline Uint16 SDL_Swap16(Uint16);
140 #pragma aux SDL_Swap16 = \
141  "xchg al, ah" \
142  parm [ax] \
143  modify [ax];
144 #else
147 {
148  return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
149 }
150 #endif
151 
152 #if (defined(__clang__) && (__clang_major__ > 2 || (__clang_major__ == 2 && __clang_minor__ >= 6))) || \
153  (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)))
154 #define SDL_Swap32(x) __builtin_bswap32(x)
155 #elif defined(__GNUC__) && defined(__i386__) && \
156  !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
159 {
160  __asm__("bswap %0": "=r"(x):"0"(x));
161  return x;
162 }
163 #elif defined(__GNUC__) && defined(__x86_64__)
166 {
167  __asm__("bswapl %0": "=r"(x):"0"(x));
168  return x;
169 }
170 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
173 {
174  Uint32 result;
175 
176  __asm__("rlwimi %0,%2,24,16,23": "=&r"(result): "0" (x>>24), "r"(x));
177  __asm__("rlwimi %0,%2,8,8,15" : "=&r"(result): "0" (result), "r"(x));
178  __asm__("rlwimi %0,%2,24,0,7" : "=&r"(result): "0" (result), "r"(x));
179  return result;
180 }
181 #elif defined(__GNUC__) && defined(__aarch64__)
184 {
185  __asm__("rev %w1, %w0": "=r"(x):"r"(x));
186  return x;
187 }
188 #elif defined(__GNUC__) && (defined(__m68k__) && !defined(__mcoldfire__))
191 {
192  __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
193  return x;
194 }
195 #elif defined(__WATCOMC__) && defined(__386__)
196 extern _inline Uint32 SDL_Swap32(Uint32);
197 #pragma aux SDL_Swap32 = \
198  "bswap eax" \
199  parm [eax] \
200  modify [eax];
201 #elif defined(_MSC_VER)
202 #pragma intrinsic(_byteswap_ulong)
203 #define SDL_Swap32(x) _byteswap_ulong(x)
204 #else
207 {
208  return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
209  ((x >> 8) & 0x0000FF00) | (x >> 24)));
210 }
211 #endif
212 
213 #if (defined(__clang__) && (__clang_major__ > 2 || (__clang_major__ == 2 && __clang_minor__ >= 6))) || \
214  (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)))
215 #define SDL_Swap64(x) __builtin_bswap64(x)
216 #elif defined(__GNUC__) && defined(__i386__) && \
217  !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
220 {
221  union {
222  struct {
223  Uint32 a, b;
224  } s;
225  Uint64 u;
226  } v;
227  v.u = x;
228  __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
229  : "=r"(v.s.a), "=r"(v.s.b)
230  : "0" (v.s.a), "1"(v.s.b));
231  return v.u;
232 }
233 #elif defined(__GNUC__) && defined(__x86_64__)
236 {
237  __asm__("bswapq %0": "=r"(x):"0"(x));
238  return x;
239 }
240 #elif defined(__WATCOMC__) && defined(__386__)
241 extern _inline Uint64 SDL_Swap64(Uint64);
242 #pragma aux SDL_Swap64 = \
243  "bswap eax" \
244  "bswap edx" \
245  "xchg eax,edx" \
246  parm [eax edx] \
247  modify [eax edx];
248 #elif defined(_MSC_VER)
249 #pragma intrinsic(_byteswap_uint64)
250 #define SDL_Swap64(x) _byteswap_uint64(x)
251 #else
254 {
255  Uint32 hi, lo;
256 
257  /* Separate into high and low 32-bit values and swap them */
258  lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
259  x >>= 32;
260  hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
261  x = SDL_Swap32(lo);
262  x <<= 32;
263  x |= SDL_Swap32(hi);
264  return (x);
265 }
266 #endif
267 
268 
269 SDL_FORCE_INLINE float
271 {
272  union {
273  float f;
274  Uint32 ui32;
275  } swapper;
276  swapper.f = x;
277  swapper.ui32 = SDL_Swap32(swapper.ui32);
278  return swapper.f;
279 }
280 
281 
282 /**
283  * \name Swap to native
284  * Byteswap item from the specified endianness to the native endianness.
285  */
286 /* @{ */
287 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
288 #define SDL_SwapLE16(X) (X)
289 #define SDL_SwapLE32(X) (X)
290 #define SDL_SwapLE64(X) (X)
291 #define SDL_SwapFloatLE(X) (X)
292 #define SDL_SwapBE16(X) SDL_Swap16(X)
293 #define SDL_SwapBE32(X) SDL_Swap32(X)
294 #define SDL_SwapBE64(X) SDL_Swap64(X)
295 #define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
296 #else
297 #define SDL_SwapLE16(X) SDL_Swap16(X)
298 #define SDL_SwapLE32(X) SDL_Swap32(X)
299 #define SDL_SwapLE64(X) SDL_Swap64(X)
300 #define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
301 #define SDL_SwapBE16(X) (X)
302 #define SDL_SwapBE32(X) (X)
303 #define SDL_SwapBE64(X) (X)
304 #define SDL_SwapFloatBE(X) (X)
305 #endif
306 /* @} *//* Swap to native */
307 
308 /* Ends C function definitions when using C++ */
309 #ifdef __cplusplus
310 }
311 #endif
312 #include "close_code.h"
313 
314 #endif /* SDL_endian_h_ */
315 
316 /* vi: set ts=4 sw=4 expandtab: */
SDL_FORCE_INLINE Uint32 SDL_Swap32(Uint32 x)
Definition: SDL_endian.h:206
SDL_FORCE_INLINE Uint16 SDL_Swap16(Uint16 x)
Definition: SDL_endian.h:146
SDL_FORCE_INLINE float SDL_SwapFloat(float x)
Definition: SDL_endian.h:270
SDL_FORCE_INLINE Uint64 SDL_Swap64(Uint64 x)
Definition: SDL_endian.h:253
uint16_t Uint16
Definition: SDL_stdinc.h:197
#define SDL_static_cast(type, expression)
Definition: SDL_stdinc.h:144
uint64_t Uint64
Definition: SDL_stdinc.h:222
uint32_t Uint32
Definition: SDL_stdinc.h:209
#define __inline__
Definition: begin_code.h:132
#define SDL_FORCE_INLINE
Definition: begin_code.h:143