SDL: include/SDL_endian.h@601b0e251822

     1 /*

     2   Simple DirectMedia Layer

     3   Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

     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.

     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:

    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 */

    22 /**

    23  *  \file SDL_endian.h

    24  *

    25  *  Functions for reading and writing endian-specific values

    26  */

    28 #ifndef _SDL_endian_h

    29 #define _SDL_endian_h

    31 #include "SDL_stdinc.h"

    33 /**

    34  *  \name The two types of endianness

    35  */

    36 /*@{*/

    37 #define SDL_LIL_ENDIAN	1234

    38 #define SDL_BIG_ENDIAN	4321

    39 /*@}*/

    41 #ifndef SDL_BYTEORDER           /* Not defined in SDL_config.h? */

    42 #ifdef __linux__

    43 #include <endian.h>

    44 #define SDL_BYTEORDER  __BYTE_ORDER

    45 #else /* __linux __ */

    46 #if defined(__hppa__) || \

    47     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \

    48     (defined(__MIPS__) && defined(__MISPEB__)) || \

    49     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \

    50     defined(__sparc__)

    51 #define SDL_BYTEORDER	SDL_BIG_ENDIAN

    52 #else

    53 #define SDL_BYTEORDER	SDL_LIL_ENDIAN

    54 #endif

    55 #endif /* __linux __ */

    56 #endif /* !SDL_BYTEORDER */

    59 #include "begin_code.h"

    60 /* Set up for C function definitions, even when using C++ */

    61 #ifdef __cplusplus

    62 /* *INDENT-OFF* */

    63 extern "C" {

    64 /* *INDENT-ON* */

    65 #endif

    67 /**

    68  *  \file SDL_endian.h

    69  *

    70  *  Uses inline functions for compilers that support them, and static

    71  *  functions for those that do not.  Because these functions become

    72  *  static for compilers that do not support inline functions, this

    73  *  header should only be included in files that actually use them.

    74  */

    75 #if defined(__GNUC__) && defined(__i386__) && \

    76    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)

    77 static __inline__ Uint16

    78 SDL_Swap16(Uint16 x)

    79 {

    80   __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));

    81     return x;

    82 }

    83 #elif defined(__GNUC__) && defined(__x86_64__)

    84 static __inline__ Uint16

    85 SDL_Swap16(Uint16 x)

    86 {

    87   __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));

    88     return x;

    89 }

    90 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))

    91 static __inline__ Uint16

    92 SDL_Swap16(Uint16 x)

    93 {

    94     int result;

    96   __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));

    97     return (Uint16)result;

    98 }

    99 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)

   100 static __inline__ Uint16

   101 SDL_Swap16(Uint16 x)

   102 {

   103   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");

   104     return x;

   105 }

   106 #else

   107 static __inline__ Uint16

   108 SDL_Swap16(Uint16 x)

   109 {

   110     return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));

   111 }

   112 #endif

   114 #if defined(__GNUC__) && defined(__i386__)

   115 static __inline__ Uint32

   116 SDL_Swap32(Uint32 x)

   117 {

   118   __asm__("bswap %0": "=r"(x):"0"(x));

   119     return x;

   120 }

   121 #elif defined(__GNUC__) && defined(__x86_64__)

   122 static __inline__ Uint32

   123 SDL_Swap32(Uint32 x)

   124 {

   125   __asm__("bswapl %0": "=r"(x):"0"(x));

   126     return x;

   127 }

   128 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))

   129 static __inline__ Uint32

   130 SDL_Swap32(Uint32 x)

   131 {

   132     Uint32 result;

   134   __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));

   135   __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));

   136   __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));

   137     return result;

   138 }

   139 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)

   140 static __inline__ Uint32

   141 SDL_Swap32(Uint32 x)

   142 {

   143   __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");

   144     return x;

   145 }

   146 #else

   147 static __inline__ Uint32

   148 SDL_Swap32(Uint32 x)

   149 {

   150     return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |

   151                                     ((x >> 8) & 0x0000FF00) | (x >> 24)));

   152 }

   153 #endif

   155 #if defined(__GNUC__) && defined(__i386__)

   156 static __inline__ Uint64

   157 SDL_Swap64(Uint64 x)

   158 {

   159     union

   160     {

   161         struct

   162         {

   163             Uint32 a, b;

   164         } s;

   165         Uint64 u;

   166     } v;

   167     v.u = x;

   168   __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),

   169             "1"(v.s.

   170                 b));

   171     return v.u;

   172 }

   173 #elif defined(__GNUC__) && defined(__x86_64__)

   174 static __inline__ Uint64

   175 SDL_Swap64(Uint64 x)

   176 {

   177   __asm__("bswapq %0": "=r"(x):"0"(x));

   178     return x;

   179 }

   180 #else

   181 static __inline__ Uint64

   182 SDL_Swap64(Uint64 x)

   183 {

   184     Uint32 hi, lo;

   186     /* Separate into high and low 32-bit values and swap them */

   187     lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);

   188     x >>= 32;

   189     hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);

   190     x = SDL_Swap32(lo);

   191     x <<= 32;

   192     x |= SDL_Swap32(hi);

   193     return (x);

   194 }

   195 #endif

   198 static __inline__ float

   199 SDL_SwapFloat(float x)

   200 {

   201     union

   202     {

   203         float f;

   204         Uint32 ui32;

   205     } swapper;

   206     swapper.f = x;

   207     swapper.ui32 = SDL_Swap32(swapper.ui32);

   208     return swapper.f;

   209 }

   212 /**

   213  *  \name Swap to native

   214  *  Byteswap item from the specified endianness to the native endianness.

   215  */

   216 /*@{*/

   217 #if SDL_BYTEORDER == SDL_LIL_ENDIAN

   218 #define SDL_SwapLE16(X)	(X)

   219 #define SDL_SwapLE32(X)	(X)

   220 #define SDL_SwapLE64(X)	(X)

   221 #define SDL_SwapFloatLE(X)	(X)

   222 #define SDL_SwapBE16(X)	SDL_Swap16(X)

   223 #define SDL_SwapBE32(X)	SDL_Swap32(X)

   224 #define SDL_SwapBE64(X)	SDL_Swap64(X)

   225 #define SDL_SwapFloatBE(X)	SDL_SwapFloat(X)

   226 #else

   227 #define SDL_SwapLE16(X)	SDL_Swap16(X)

   228 #define SDL_SwapLE32(X)	SDL_Swap32(X)

   229 #define SDL_SwapLE64(X)	SDL_Swap64(X)

   230 #define SDL_SwapFloatLE(X)	SDL_SwapFloat(X)

   231 #define SDL_SwapBE16(X)	(X)

   232 #define SDL_SwapBE32(X)	(X)

   233 #define SDL_SwapBE64(X)	(X)

   234 #define SDL_SwapFloatBE(X)	(X)

   235 #endif

   236 /*@}*//*Swap to native*/

   238 /* Ends C function definitions when using C++ */

   239 #ifdef __cplusplus

   240 /* *INDENT-OFF* */

   241 }

   242 /* *INDENT-ON* */

   243 #endif

   244 #include "close_code.h"

   246 #endif /* _SDL_endian_h */

   248 /* vi: set ts=4 sw=4 expandtab: */

author	Ryan C. Gordon <icculus@icculus.org>
	Mon Apr 09 23:55:43 2012 -0400
changeset 6305	601b0e251822
parent 6138	4c64952a58fb
permissions	-rw-r--r--