dep/sdl/include/SDL_endian.h

   1 /*
   2   Simple DirectMedia Layer
   3   Copyright (C) 1997-2023 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__) || 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
 116 extern "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)
 144 #pragma intrinsic(_byteswap_ushort)
 145 #define SDL_Swap16(x) _byteswap_ushort(x)
 146 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
 147 SDL_FORCE_INLINE Uint16
 148 SDL_Swap16(Uint16 x)
 149 {
 150   __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
 151     return x;
 152 }
 153 #elif defined(__x86_64__)
 154 SDL_FORCE_INLINE Uint16
 155 SDL_Swap16(Uint16 x)
 156 {
 157   __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
 158     return x;
 159 }
 160 #elif (defined(__powerpc__) || defined(__ppc__))
 161 SDL_FORCE_INLINE Uint16
 162 SDL_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__))
 170 SDL_FORCE_INLINE Uint16
 171 SDL_Swap16(Uint16 x)
 172 {
 173   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
 174     return x;
 175 }
 176 #elif defined(__WATCOMC__) && defined(__386__)
 177 extern __inline Uint16 SDL_Swap16(Uint16);
 178 #pragma aux SDL_Swap16 = \
 179   "xchg al, ah" \
 180   parm   [ax]   \
 181   modify [ax];
 182 #else
 183 SDL_FORCE_INLINE Uint16
 184 SDL_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)
 193 #pragma intrinsic(_byteswap_ulong)
 194 #define SDL_Swap32(x) _byteswap_ulong(x)
 195 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
 196 SDL_FORCE_INLINE Uint32
 197 SDL_Swap32(Uint32 x)
 198 {
 199   __asm__("bswap %0": "=r"(x):"0"(x));
 200     return x;
 201 }
 202 #elif defined(__x86_64__)
 203 SDL_FORCE_INLINE Uint32
 204 SDL_Swap32(Uint32 x)
 205 {
 206   __asm__("bswapl %0": "=r"(x):"0"(x));
 207     return x;
 208 }
 209 #elif (defined(__powerpc__) || defined(__ppc__))
 210 SDL_FORCE_INLINE Uint32
 211 SDL_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__))
 221 SDL_FORCE_INLINE Uint32
 222 SDL_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__)
 228 extern __inline Uint32 SDL_Swap32(Uint32);
 229 #pragma aux SDL_Swap32 = \
 230   "bswap eax"  \
 231   parm   [eax] \
 232   modify [eax];
 233 #else
 234 SDL_FORCE_INLINE Uint32
 235 SDL_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)
 245 #pragma intrinsic(_byteswap_uint64)
 246 #define SDL_Swap64(x) _byteswap_uint64(x)
 247 #elif defined(__i386__) && !HAS_BROKEN_BSWAP
 248 SDL_FORCE_INLINE Uint64
 249 SDL_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__)
 264 SDL_FORCE_INLINE Uint64
 265 SDL_Swap64(Uint64 x)
 266 {
 267   __asm__("bswapq %0": "=r"(x):"0"(x));
 268     return x;
 269 }
 270 #elif defined(__WATCOMC__) && defined(__386__)
 271 extern __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
 279 SDL_FORCE_INLINE Uint64
 280 SDL_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
 296 SDL_FORCE_INLINE float
 297 SDL_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: */