include/SDL_endian.h
author Paul Hunkin <paul@bieh.net>
Mon, 17 May 2010 15:14:34 +1200
changeset 4695 b7918263da92
parent 4439 ab63fdcf66af
child 4552 116f05eb67c7
permissions -rw-r--r--
Initial commit, adding __ANDROID__ to the platform list
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2010 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 /**
    24  *  \file SDL_endian.h
    25  *  
    26  *  Functions for reading and writing endian-specific values
    27  */
    28 
    29 #ifndef _SDL_endian_h
    30 #define _SDL_endian_h
    31 
    32 #include "SDL_stdinc.h"
    33 
    34 /**
    35  *  \name The two types of endianness
    36  */
    37 /*@{*/
    38 #define SDL_LIL_ENDIAN	1234
    39 #define SDL_BIG_ENDIAN	4321
    40 /*@}*/
    41 
    42 #ifndef SDL_BYTEORDER           /* Not defined in SDL_config.h? */
    43 #if defined(__hppa__) || \
    44     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
    45     (defined(__MIPS__) && defined(__MISPEB__)) || \
    46     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
    47     defined(__sparc__)
    48 #define SDL_BYTEORDER	SDL_BIG_ENDIAN
    49 #else
    50 #define SDL_BYTEORDER	SDL_LIL_ENDIAN
    51 #endif
    52 #endif /* !SDL_BYTEORDER */
    53 
    54 
    55 #include "begin_code.h"
    56 /* Set up for C function definitions, even when using C++ */
    57 #ifdef __cplusplus
    58 /* *INDENT-OFF* */
    59 extern "C" {
    60 /* *INDENT-ON* */
    61 #endif
    62 
    63 /**
    64  *  \file SDL_endian.h
    65  *  
    66  *  Uses inline functions for compilers that support them, and static
    67  *  functions for those that do not.  Because these functions become
    68  *  static for compilers that do not support inline functions, this
    69  *  header should only be included in files that actually use them.
    70  */
    71 #if defined(__GNUC__) && defined(__i386__) && \
    72    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
    73 static __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 static __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 static __inline__ Uint16
    88 SDL_Swap16(Uint16 x)
    89 {
    90     Uint16 result;
    91 
    92   __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
    93     return result;
    94 }
    95 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
    96 static __inline__ Uint16
    97 SDL_Swap16(Uint16 x)
    98 {
    99   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
   100     return x;
   101 }
   102 #else
   103 static __inline__ Uint16
   104 SDL_Swap16(Uint16 x)
   105 {
   106     return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
   107 }
   108 #endif
   109 
   110 #if defined(__GNUC__) && defined(__i386__)
   111 static __inline__ Uint32
   112 SDL_Swap32(Uint32 x)
   113 {
   114   __asm__("bswap %0": "=r"(x):"0"(x));
   115     return x;
   116 }
   117 #elif defined(__GNUC__) && defined(__x86_64__)
   118 static __inline__ Uint32
   119 SDL_Swap32(Uint32 x)
   120 {
   121   __asm__("bswapl %0": "=r"(x):"0"(x));
   122     return x;
   123 }
   124 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
   125 static __inline__ Uint32
   126 SDL_Swap32(Uint32 x)
   127 {
   128     Uint32 result;
   129 
   130   __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
   131   __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
   132   __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
   133     return result;
   134 }
   135 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
   136 static __inline__ Uint32
   137 SDL_Swap32(Uint32 x)
   138 {
   139   __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
   140     return x;
   141 }
   142 #else
   143 static __inline__ Uint32
   144 SDL_Swap32(Uint32 x)
   145 {
   146     return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
   147                                     ((x >> 8) & 0x0000FF00) | (x >> 24)));
   148 }
   149 #endif
   150 
   151 #ifdef SDL_HAS_64BIT_TYPE
   152 #if defined(__GNUC__) && defined(__i386__)
   153 static __inline__ Uint64
   154 SDL_Swap64(Uint64 x)
   155 {
   156     union
   157     {
   158         struct
   159         {
   160             Uint32 a, b;
   161         } s;
   162         Uint64 u;
   163     } v;
   164     v.u = x;
   165   __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
   166             "1"(v.s.
   167                 b));
   168     return v.u;
   169 }
   170 #elif defined(__GNUC__) && defined(__x86_64__)
   171 static __inline__ Uint64
   172 SDL_Swap64(Uint64 x)
   173 {
   174   __asm__("bswapq %0": "=r"(x):"0"(x));
   175     return x;
   176 }
   177 #else
   178 static __inline__ Uint64
   179 SDL_Swap64(Uint64 x)
   180 {
   181     Uint32 hi, lo;
   182 
   183     /* Separate into high and low 32-bit values and swap them */
   184     lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   185     x >>= 32;
   186     hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   187     x = SDL_Swap32(lo);
   188     x <<= 32;
   189     x |= SDL_Swap32(hi);
   190     return (x);
   191 }
   192 #endif
   193 #else
   194 /**
   195  *  This is mainly to keep compilers from complaining in SDL code.
   196  *  If there is no real 64-bit datatype, then compilers will complain about
   197  *  the fake 64-bit datatype that SDL provides when it compiles user code.
   198  */
   199 #define SDL_Swap64(X)	(X)
   200 #endif /* SDL_HAS_64BIT_TYPE */
   201 
   202 
   203 static __inline__ float
   204 SDL_SwapFloat(float x)
   205 {
   206     union
   207     {
   208         float f;
   209         Uint32 ui32;
   210     } swapper;
   211     swapper.f = x;
   212     swapper.ui32 = SDL_Swap32(swapper.ui32);
   213     return swapper.f;
   214 }
   215 
   216 
   217 /**
   218  *  \name Swap to native
   219  *  Byteswap item from the specified endianness to the native endianness.
   220  */
   221 /*@{*/
   222 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   223 #define SDL_SwapLE16(X)	(X)
   224 #define SDL_SwapLE32(X)	(X)
   225 #define SDL_SwapLE64(X)	(X)
   226 #define SDL_SwapFloatLE(X)	(X)
   227 #define SDL_SwapBE16(X)	SDL_Swap16(X)
   228 #define SDL_SwapBE32(X)	SDL_Swap32(X)
   229 #define SDL_SwapBE64(X)	SDL_Swap64(X)
   230 #define SDL_SwapFloatBE(X)	SDL_SwapFloat(X)
   231 #else
   232 #define SDL_SwapLE16(X)	SDL_Swap16(X)
   233 #define SDL_SwapLE32(X)	SDL_Swap32(X)
   234 #define SDL_SwapLE64(X)	SDL_Swap64(X)
   235 #define SDL_SwapFloatLE(X)	SDL_SwapFloat(X)
   236 #define SDL_SwapBE16(X)	(X)
   237 #define SDL_SwapBE32(X)	(X)
   238 #define SDL_SwapBE64(X)	(X)
   239 #define SDL_SwapFloatBE(X)	(X)
   240 #endif
   241 /*@}*//*Swap to native*/
   242 
   243 /* Ends C function definitions when using C++ */
   244 #ifdef __cplusplus
   245 /* *INDENT-OFF* */
   246 }
   247 /* *INDENT-ON* */
   248 #endif
   249 #include "close_code.h"
   250 
   251 #endif /* _SDL_endian_h */
   252 
   253 /* vi: set ts=4 sw=4 expandtab: */