SDL_endian.h

00001 /*
00002   Simple DirectMedia Layer
00003   Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
00004 
00005   This software is provided 'as-is', without any express or implied
00006   warranty.  In no event will the authors be held liable for any damages
00007   arising from the use of this software.
00008 
00009   Permission is granted to anyone to use this software for any purpose,
00010   including commercial applications, and to alter it and redistribute it
00011   freely, subject to the following restrictions:
00012 
00013   1. The origin of this software must not be misrepresented; you must not
00014      claim that you wrote the original software. If you use this software
00015      in a product, an acknowledgment in the product documentation would be
00016      appreciated but is not required.
00017   2. Altered source versions must be plainly marked as such, and must not be
00018      misrepresented as being the original software.
00019   3. This notice may not be removed or altered from any source distribution.
00020 */
00021 
00022 /**
00023  *  \file SDL_endian.h
00024  *
00025  *  Functions for reading and writing endian-specific values
00026  */
00027 
00028 #ifndef _SDL_endian_h
00029 #define _SDL_endian_h
00030 
00031 #include "SDL_stdinc.h"
00032 
00033 /**
00034  *  \name The two types of endianness
00035  */
00036 /* @{ */
00037 #define SDL_LIL_ENDIAN  1234
00038 #define SDL_BIG_ENDIAN  4321
00039 /* @} */
00040 
00041 #ifndef SDL_BYTEORDER           /* Not defined in SDL_config.h? */
00042 #ifdef __linux__
00043 #include <endian.h>
00044 #define SDL_BYTEORDER  __BYTE_ORDER
00045 #else /* __linux __ */
00046 #if defined(__hppa__) || \
00047     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
00048     (defined(__MIPS__) && defined(__MISPEB__)) || \
00049     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
00050     defined(__sparc__)
00051 #define SDL_BYTEORDER   SDL_BIG_ENDIAN
00052 #else
00053 #define SDL_BYTEORDER   SDL_LIL_ENDIAN
00054 #endif
00055 #endif /* __linux __ */
00056 #endif /* !SDL_BYTEORDER */
00057 
00058 
00059 #include "begin_code.h"
00060 /* Set up for C function definitions, even when using C++ */
00061 #ifdef __cplusplus
00062 extern "C" {
00063 #endif
00064 
00065 /**
00066  *  \file SDL_endian.h
00067  */
00068 #if defined(__GNUC__) && defined(__i386__) && \
00069    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
00070 SDL_FORCE_INLINE Uint16
00071 SDL_Swap16(Uint16 x)
00072 {
00073   __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
00074     return x;
00075 }
00076 #elif defined(__GNUC__) && defined(__x86_64__)
00077 SDL_FORCE_INLINE Uint16
00078 SDL_Swap16(Uint16 x)
00079 {
00080   __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
00081     return x;
00082 }
00083 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
00084 SDL_FORCE_INLINE Uint16
00085 SDL_Swap16(Uint16 x)
00086 {
00087     int result;
00088 
00089   __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
00090     return (Uint16)result;
00091 }
00092 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
00093 SDL_FORCE_INLINE Uint16
00094 SDL_Swap16(Uint16 x)
00095 {
00096   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
00097     return x;
00098 }
00099 #else
00100 SDL_FORCE_INLINE Uint16
00101 SDL_Swap16(Uint16 x)
00102 {
00103     return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
00104 }
00105 #endif
00106 
00107 #if defined(__GNUC__) && defined(__i386__)
00108 SDL_FORCE_INLINE Uint32
00109 SDL_Swap32(Uint32 x)
00110 {
00111   __asm__("bswap %0": "=r"(x):"0"(x));
00112     return x;
00113 }
00114 #elif defined(__GNUC__) && defined(__x86_64__)
00115 SDL_FORCE_INLINE Uint32
00116 SDL_Swap32(Uint32 x)
00117 {
00118   __asm__("bswapl %0": "=r"(x):"0"(x));
00119     return x;
00120 }
00121 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
00122 SDL_FORCE_INLINE Uint32
00123 SDL_Swap32(Uint32 x)
00124 {
00125     Uint32 result;
00126 
00127   __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
00128   __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
00129   __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
00130     return result;
00131 }
00132 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
00133 SDL_FORCE_INLINE Uint32
00134 SDL_Swap32(Uint32 x)
00135 {
00136   __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
00137     return x;
00138 }
00139 #else
00140 SDL_FORCE_INLINE Uint32
00141 SDL_Swap32(Uint32 x)
00142 {
00143     return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
00144                                     ((x >> 8) & 0x0000FF00) | (x >> 24)));
00145 }
00146 #endif
00147 
00148 #if defined(__GNUC__) && defined(__i386__)
00149 SDL_FORCE_INLINE Uint64
00150 SDL_Swap64(Uint64 x)
00151 {
00152     union
00153     {
00154         struct
00155         {
00156             Uint32 a, b;
00157         } s;
00158         Uint64 u;
00159     } v;
00160     v.u = x;
00161   __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
00162             "1"(v.s.
00163                 b));
00164     return v.u;
00165 }
00166 #elif defined(__GNUC__) && defined(__x86_64__)
00167 SDL_FORCE_INLINE Uint64
00168 SDL_Swap64(Uint64 x)
00169 {
00170   __asm__("bswapq %0": "=r"(x):"0"(x));
00171     return x;
00172 }
00173 #else
00174 SDL_FORCE_INLINE Uint64
00175 SDL_Swap64(Uint64 x)
00176 {
00177     Uint32 hi, lo;
00178 
00179     /* Separate into high and low 32-bit values and swap them */
00180     lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
00181     x >>= 32;
00182     hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
00183     x = SDL_Swap32(lo);
00184     x <<= 32;
00185     x |= SDL_Swap32(hi);
00186     return (x);
00187 }
00188 #endif
00189 
00190 
00191 SDL_FORCE_INLINE float
00192 SDL_SwapFloat(float x)
00193 {
00194     union
00195     {
00196         float f;
00197         Uint32 ui32;
00198     } swapper;
00199     swapper.f = x;
00200     swapper.ui32 = SDL_Swap32(swapper.ui32);
00201     return swapper.f;
00202 }
00203 
00204 
00205 /**
00206  *  \name Swap to native
00207  *  Byteswap item from the specified endianness to the native endianness.
00208  */
00209 /* @{ */
00210 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
00211 #define SDL_SwapLE16(X) (X)
00212 #define SDL_SwapLE32(X) (X)
00213 #define SDL_SwapLE64(X) (X)
00214 #define SDL_SwapFloatLE(X)  (X)
00215 #define SDL_SwapBE16(X) SDL_Swap16(X)
00216 #define SDL_SwapBE32(X) SDL_Swap32(X)
00217 #define SDL_SwapBE64(X) SDL_Swap64(X)
00218 #define SDL_SwapFloatBE(X)  SDL_SwapFloat(X)
00219 #else
00220 #define SDL_SwapLE16(X) SDL_Swap16(X)
00221 #define SDL_SwapLE32(X) SDL_Swap32(X)
00222 #define SDL_SwapLE64(X) SDL_Swap64(X)
00223 #define SDL_SwapFloatLE(X)  SDL_SwapFloat(X)
00224 #define SDL_SwapBE16(X) (X)
00225 #define SDL_SwapBE32(X) (X)
00226 #define SDL_SwapBE64(X) (X)
00227 #define SDL_SwapFloatBE(X)  (X)
00228 #endif
00229 /* @} *//* Swap to native */
00230 
00231 /* Ends C function definitions when using C++ */
00232 #ifdef __cplusplus
00233 }
00234 #endif
00235 #include "close_code.h"
00236 
00237 #endif /* _SDL_endian_h */
00238 
00239 /* vi: set ts=4 sw=4 expandtab: */