1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2024 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
39static __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__) || defined(__DragonFly__)
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/* predefs from newer gcc and clang versions: */
69#elif defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_BIG_ENDIAN__) && defined(__BYTE_ORDER__)
70#if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
71#define SDL_BYTEORDER SDL_LIL_ENDIAN
72#elif (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
73#define SDL_BYTEORDER SDL_BIG_ENDIAN
74#else
75#error Unsupported endianness
76#endif /**/
77#else
78#if defined(__hppa__) || \
79 defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
80 (defined(__MIPS__) && defined(__MIPSEB__)) || \
81 defined(__ppc__) || defined(__POWERPC__) || defined(__powerpc__) || defined(__PPC__) || \
82 defined(__sparc__)
83#define SDL_BYTEORDER SDL_BIG_ENDIAN
84#else
85#define SDL_BYTEORDER SDL_LIL_ENDIAN
86#endif
87#endif /* __linux__ */
88#endif /* !SDL_BYTEORDER */
89
90#ifndef SDL_FLOATWORDORDER /* Not defined in SDL_config.h? */
91/* predefs from newer gcc versions: */
92#if defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_BIG_ENDIAN__) && defined(__FLOAT_WORD_ORDER__)
93#if (__FLOAT_WORD_ORDER__ == __ORDER_LITTLE_ENDIAN__)
94#define SDL_FLOATWORDORDER SDL_LIL_ENDIAN
95#elif (__FLOAT_WORD_ORDER__ == __ORDER_BIG_ENDIAN__)
96#define SDL_FLOATWORDORDER SDL_BIG_ENDIAN
97#else
98#error Unsupported endianness
99#endif /**/
100#elif defined(__MAVERICK__)
101/* For Maverick, float words are always little-endian. */
102#define SDL_FLOATWORDORDER SDL_LIL_ENDIAN
103#elif (defined(__arm__) || defined(__thumb__)) && !defined(__VFP_FP__) && !defined(__ARM_EABI__)
104/* For FPA, float words are always big-endian. */
105#define SDL_FLOATWORDORDER SDL_BIG_ENDIAN
106#else
107/* By default, assume that floats words follow the memory system mode. */
108#define SDL_FLOATWORDORDER SDL_BYTEORDER
109#endif /* __FLOAT_WORD_ORDER__ */
110#endif /* !SDL_FLOATWORDORDER */
111
112
113#include "begin_code.h"
114/* Set up for C function definitions, even when using C++ */
115#ifdef __cplusplus
116extern "C" {
117#endif
118
119/**
120 * \file SDL_endian.h
121 */
122
123/* various modern compilers may have builtin swap */
124#if defined(__GNUC__) || defined(__clang__)
125# define HAS_BUILTIN_BSWAP16 (_SDL_HAS_BUILTIN(__builtin_bswap16)) || \
126 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))
127# define HAS_BUILTIN_BSWAP32 (_SDL_HAS_BUILTIN(__builtin_bswap32)) || \
128 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
129# define HAS_BUILTIN_BSWAP64 (_SDL_HAS_BUILTIN(__builtin_bswap64)) || \
130 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
131
132 /* this one is broken */
133# define HAS_BROKEN_BSWAP (__GNUC__ == 2 && __GNUC_MINOR__ <= 95)
134#else
135# define HAS_BUILTIN_BSWAP16 0
136# define HAS_BUILTIN_BSWAP32 0
137# define HAS_BUILTIN_BSWAP64 0
138# define HAS_BROKEN_BSWAP 0
139#endif
140
141#if HAS_BUILTIN_BSWAP16
142#define SDL_Swap16(x) __builtin_bswap16(x)
143#elif (defined(_MSC_VER) && (_MSC_VER >= 1400)) && !defined(__ICL)
144#pragma intrinsic(_byteswap_ushort)
145#define SDL_Swap16(x) _byteswap_ushort(x)
146#elif defined(__i386__) && !HAS_BROKEN_BSWAP
147SDL_FORCE_INLINE Uint16
148SDL_Swap16(Uint16 x)
149{
150 __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
151 return x;
152}
153#elif defined(__x86_64__)
154SDL_FORCE_INLINE Uint16
155SDL_Swap16(Uint16 x)
156{
157 __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
158 return x;
159}
160#elif (defined(__powerpc__) || defined(__ppc__))
161SDL_FORCE_INLINE Uint16
162SDL_Swap16(Uint16 x)
163{
164 int result;
165
166 __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
167 return (Uint16)result;
168}
169#elif (defined(__m68k__) && !defined(__mcoldfire__))
170SDL_FORCE_INLINE Uint16
171SDL_Swap16(Uint16 x)
172{
173 __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
174 return x;
175}
176#elif defined(__WATCOMC__) && defined(__386__)
177extern __inline Uint16 SDL_Swap16(Uint16);
178#pragma aux SDL_Swap16 = \
179 "xchg al, ah" \
180 parm [ax] \
181 modify [ax];
182#else
183SDL_FORCE_INLINE Uint16
184SDL_Swap16(Uint16 x)
185{
186 return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
187}
188#endif
189
190#if HAS_BUILTIN_BSWAP32
191#define SDL_Swap32(x) __builtin_bswap32(x)
192#elif (defined(_MSC_VER) && (_MSC_VER >= 1400)) && !defined(__ICL)
193#pragma intrinsic(_byteswap_ulong)
194#define SDL_Swap32(x) _byteswap_ulong(x)
195#elif defined(__i386__) && !HAS_BROKEN_BSWAP
196SDL_FORCE_INLINE Uint32
197SDL_Swap32(Uint32 x)
198{
199 __asm__("bswap %0": "=r"(x):"0"(x));
200 return x;
201}
202#elif defined(__x86_64__)
203SDL_FORCE_INLINE Uint32
204SDL_Swap32(Uint32 x)
205{
206 __asm__("bswapl %0": "=r"(x):"0"(x));
207 return x;
208}
209#elif (defined(__powerpc__) || defined(__ppc__))
210SDL_FORCE_INLINE Uint32
211SDL_Swap32(Uint32 x)
212{
213 Uint32 result;
214
215 __asm__("rlwimi %0,%2,24,16,23": "=&r"(result): "0" (x>>24), "r"(x));
216 __asm__("rlwimi %0,%2,8,8,15" : "=&r"(result): "0" (result), "r"(x));
217 __asm__("rlwimi %0,%2,24,0,7" : "=&r"(result): "0" (result), "r"(x));
218 return result;
219}
220#elif (defined(__m68k__) && !defined(__mcoldfire__))
221SDL_FORCE_INLINE Uint32
222SDL_Swap32(Uint32 x)
223{
224 __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
225 return x;
226}
227#elif defined(__WATCOMC__) && defined(__386__)
228extern __inline Uint32 SDL_Swap32(Uint32);
229#pragma aux SDL_Swap32 = \
230 "bswap eax" \
231 parm [eax] \
232 modify [eax];
233#else
234SDL_FORCE_INLINE Uint32
235SDL_Swap32(Uint32 x)
236{
237 return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
238 ((x >> 8) & 0x0000FF00) | (x >> 24)));
239}
240#endif
241
242#if HAS_BUILTIN_BSWAP64
243#define SDL_Swap64(x) __builtin_bswap64(x)
244#elif (defined(_MSC_VER) && (_MSC_VER >= 1400)) && !defined(__ICL)
245#pragma intrinsic(_byteswap_uint64)
246#define SDL_Swap64(x) _byteswap_uint64(x)
247#elif defined(__i386__) && !HAS_BROKEN_BSWAP
248SDL_FORCE_INLINE Uint64
249SDL_Swap64(Uint64 x)
250{
251 union {
252 struct {
253 Uint32 a, b;
254 } s;
255 Uint64 u;
256 } v;
257 v.u = x;
258 __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
259 : "=r"(v.s.a), "=r"(v.s.b)
260 : "0" (v.s.a), "1"(v.s.b));
261 return v.u;
262}
263#elif defined(__x86_64__)
264SDL_FORCE_INLINE Uint64
265SDL_Swap64(Uint64 x)
266{
267 __asm__("bswapq %0": "=r"(x):"0"(x));
268 return x;
269}
270#elif defined(__WATCOMC__) && defined(__386__)
271extern __inline Uint64 SDL_Swap64(Uint64);
272#pragma aux SDL_Swap64 = \
273 "bswap eax" \
274 "bswap edx" \
275 "xchg eax,edx" \
276 parm [eax edx] \
277 modify [eax edx];
278#else
279SDL_FORCE_INLINE Uint64
280SDL_Swap64(Uint64 x)
281{
282 Uint32 hi, lo;
283
284 /* Separate into high and low 32-bit values and swap them */
285 lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
286 x >>= 32;
287 hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
288 x = SDL_Swap32(lo);
289 x <<= 32;
290 x |= SDL_Swap32(hi);
291 return (x);
292}
293#endif
294
295
296SDL_FORCE_INLINE float
297SDL_SwapFloat(float x)
298{
299 union {
300 float f;
301 Uint32 ui32;
302 } swapper;
303 swapper.f = x;
304 swapper.ui32 = SDL_Swap32(swapper.ui32);
305 return swapper.f;
306}
307
308/* remove extra macros */
309#undef HAS_BROKEN_BSWAP
310#undef HAS_BUILTIN_BSWAP16
311#undef HAS_BUILTIN_BSWAP32
312#undef HAS_BUILTIN_BSWAP64
313
314/**
315 * \name Swap to native
316 * Byteswap item from the specified endianness to the native endianness.
317 */
318/* @{ */
319#if SDL_BYTEORDER == SDL_LIL_ENDIAN
320#define SDL_SwapLE16(X) (X)
321#define SDL_SwapLE32(X) (X)
322#define SDL_SwapLE64(X) (X)
323#define SDL_SwapFloatLE(X) (X)
324#define SDL_SwapBE16(X) SDL_Swap16(X)
325#define SDL_SwapBE32(X) SDL_Swap32(X)
326#define SDL_SwapBE64(X) SDL_Swap64(X)
327#define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
328#else
329#define SDL_SwapLE16(X) SDL_Swap16(X)
330#define SDL_SwapLE32(X) SDL_Swap32(X)
331#define SDL_SwapLE64(X) SDL_Swap64(X)
332#define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
333#define SDL_SwapBE16(X) (X)
334#define SDL_SwapBE32(X) (X)
335#define SDL_SwapBE64(X) (X)
336#define SDL_SwapFloatBE(X) (X)
337#endif
338/* @} *//* Swap to native */
339
340/* Ends C function definitions when using C++ */
341#ifdef __cplusplus
342}
343#endif
344#include "close_code.h"
345
346#endif /* SDL_endian_h_ */
347
348/* vi: set ts=4 sw=4 expandtab: */
349

source code of include/SDL2/SDL_endian.h