include/SDL_endian.h
author stfx <stfx@hotmail.de>
Wed, 08 Jul 2020 17:28:34 +0200
changeset 13944 b8c8ce11efc7
parent 13422 fd6a12de91c7
permissions -rw-r--r--
cmake: Fix building with -DSDL_HAPTIC=Off
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2020 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 /**
    34  *  \name The two types of endianness
    35  */
    36 /* @{ */
    37 #define SDL_LIL_ENDIAN  1234
    38 #define SDL_BIG_ENDIAN  4321
    39 /* @} */
    40 
    41 #ifndef SDL_BYTEORDER           /* Not defined in SDL_config.h? */
    42 #ifdef __linux__
    43 #include <endian.h>
    44 #define SDL_BYTEORDER  __BYTE_ORDER
    45 #elif defined(__OpenBSD__)
    46 #include <endian.h>
    47 #define SDL_BYTEORDER  BYTE_ORDER
    48 #else
    49 #if defined(__hppa__) || \
    50     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
    51     (defined(__MIPS__) && defined(__MIPSEB__)) || \
    52     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
    53     defined(__sparc__)
    54 #define SDL_BYTEORDER   SDL_BIG_ENDIAN
    55 #else
    56 #define SDL_BYTEORDER   SDL_LIL_ENDIAN
    57 #endif
    58 #endif /* __linux__ */
    59 #endif /* !SDL_BYTEORDER */
    60 
    61 
    62 #include "begin_code.h"
    63 /* Set up for C function definitions, even when using C++ */
    64 #ifdef __cplusplus
    65 extern "C" {
    66 #endif
    67 
    68 /**
    69  *  \file SDL_endian.h
    70  */
    71 #if defined(__GNUC__) && defined(__i386__) && \
    72    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
    73 SDL_FORCE_INLINE Uint16
    74 SDL_Swap16(Uint16 x)
    75 {
    76   __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
    77     return x;
    78 }
    79 #elif defined(__GNUC__) && defined(__x86_64__)
    80 SDL_FORCE_INLINE Uint16
    81 SDL_Swap16(Uint16 x)
    82 {
    83   __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
    84     return x;
    85 }
    86 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
    87 SDL_FORCE_INLINE Uint16
    88 SDL_Swap16(Uint16 x)
    89 {
    90     int result;
    91 
    92   __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
    93     return (Uint16)result;
    94 }
    95 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
    96 SDL_FORCE_INLINE Uint16
    97 SDL_Swap16(Uint16 x)
    98 {
    99   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
   100     return x;
   101 }
   102 #elif defined(__WATCOMC__) && defined(__386__)
   103 extern _inline Uint16 SDL_Swap16(Uint16);
   104 #pragma aux SDL_Swap16 = \
   105   "xchg al, ah" \
   106   parm   [ax]   \
   107   modify [ax];
   108 #else
   109 SDL_FORCE_INLINE Uint16
   110 SDL_Swap16(Uint16 x)
   111 {
   112     return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
   113 }
   114 #endif
   115 
   116 #if defined(__GNUC__) && defined(__i386__)
   117 SDL_FORCE_INLINE Uint32
   118 SDL_Swap32(Uint32 x)
   119 {
   120   __asm__("bswap %0": "=r"(x):"0"(x));
   121     return x;
   122 }
   123 #elif defined(__GNUC__) && defined(__x86_64__)
   124 SDL_FORCE_INLINE Uint32
   125 SDL_Swap32(Uint32 x)
   126 {
   127   __asm__("bswapl %0": "=r"(x):"0"(x));
   128     return x;
   129 }
   130 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
   131 SDL_FORCE_INLINE Uint32
   132 SDL_Swap32(Uint32 x)
   133 {
   134     Uint32 result;
   135 
   136   __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
   137   __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
   138   __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
   139     return result;
   140 }
   141 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
   142 SDL_FORCE_INLINE Uint32
   143 SDL_Swap32(Uint32 x)
   144 {
   145   __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
   146     return x;
   147 }
   148 #elif defined(__WATCOMC__) && defined(__386__)
   149 extern _inline Uint32 SDL_Swap32(Uint32);
   150 #ifndef __SW_3 /* 486+ */
   151 #pragma aux SDL_Swap32 = \
   152   "bswap eax"  \
   153   parm   [eax] \
   154   modify [eax];
   155 #else  /* 386-only */
   156 #pragma aux SDL_Swap32 = \
   157   "xchg al, ah"  \
   158   "ror  eax, 16" \
   159   "xchg al, ah"  \
   160   parm   [eax]   \
   161   modify [eax];
   162 #endif
   163 #else
   164 SDL_FORCE_INLINE Uint32
   165 SDL_Swap32(Uint32 x)
   166 {
   167     return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
   168                                     ((x >> 8) & 0x0000FF00) | (x >> 24)));
   169 }
   170 #endif
   171 
   172 #if defined(__GNUC__) && defined(__i386__)
   173 SDL_FORCE_INLINE Uint64
   174 SDL_Swap64(Uint64 x)
   175 {
   176     union
   177     {
   178         struct
   179         {
   180             Uint32 a, b;
   181         } s;
   182         Uint64 u;
   183     } v;
   184     v.u = x;
   185   __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
   186             "1"(v.s.
   187                 b));
   188     return v.u;
   189 }
   190 #elif defined(__GNUC__) && defined(__x86_64__)
   191 SDL_FORCE_INLINE Uint64
   192 SDL_Swap64(Uint64 x)
   193 {
   194   __asm__("bswapq %0": "=r"(x):"0"(x));
   195     return x;
   196 }
   197 #else
   198 SDL_FORCE_INLINE Uint64
   199 SDL_Swap64(Uint64 x)
   200 {
   201     Uint32 hi, lo;
   202 
   203     /* Separate into high and low 32-bit values and swap them */
   204     lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   205     x >>= 32;
   206     hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   207     x = SDL_Swap32(lo);
   208     x <<= 32;
   209     x |= SDL_Swap32(hi);
   210     return (x);
   211 }
   212 #endif
   213 
   214 
   215 SDL_FORCE_INLINE float
   216 SDL_SwapFloat(float x)
   217 {
   218     union
   219     {
   220         float f;
   221         Uint32 ui32;
   222     } swapper;
   223     swapper.f = x;
   224     swapper.ui32 = SDL_Swap32(swapper.ui32);
   225     return swapper.f;
   226 }
   227 
   228 
   229 /**
   230  *  \name Swap to native
   231  *  Byteswap item from the specified endianness to the native endianness.
   232  */
   233 /* @{ */
   234 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   235 #define SDL_SwapLE16(X) (X)
   236 #define SDL_SwapLE32(X) (X)
   237 #define SDL_SwapLE64(X) (X)
   238 #define SDL_SwapFloatLE(X)  (X)
   239 #define SDL_SwapBE16(X) SDL_Swap16(X)
   240 #define SDL_SwapBE32(X) SDL_Swap32(X)
   241 #define SDL_SwapBE64(X) SDL_Swap64(X)
   242 #define SDL_SwapFloatBE(X)  SDL_SwapFloat(X)
   243 #else
   244 #define SDL_SwapLE16(X) SDL_Swap16(X)
   245 #define SDL_SwapLE32(X) SDL_Swap32(X)
   246 #define SDL_SwapLE64(X) SDL_Swap64(X)
   247 #define SDL_SwapFloatLE(X)  SDL_SwapFloat(X)
   248 #define SDL_SwapBE16(X) (X)
   249 #define SDL_SwapBE32(X) (X)
   250 #define SDL_SwapBE64(X) (X)
   251 #define SDL_SwapFloatBE(X)  (X)
   252 #endif
   253 /* @} *//* Swap to native */
   254 
   255 /* Ends C function definitions when using C++ */
   256 #ifdef __cplusplus
   257 }
   258 #endif
   259 #include "close_code.h"
   260 
   261 #endif /* SDL_endian_h_ */
   262 
   263 /* vi: set ts=4 sw=4 expandtab: */