include/SDL_endian.h
author Sam Lantinga <slouken@libsdl.org>
Mon, 17 Jan 2011 09:09:15 -0800
changeset 5009 b21ad135d86b
parent 4552 116f05eb67c7
child 5262 b530ef003506
permissions -rw-r--r--
Minor documentation consistency cleanup
     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 #ifdef __linux__
    44 #include <endian.h>
    45 #define SDL_BYTEORDER  __BYTE_ORDER
    46 #else /* __linux __ */
    47 #if defined(__hppa__) || \
    48     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
    49     (defined(__MIPS__) && defined(__MISPEB__)) || \
    50     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
    51     defined(__sparc__)
    52 #define SDL_BYTEORDER	SDL_BIG_ENDIAN
    53 #else
    54 #define SDL_BYTEORDER	SDL_LIL_ENDIAN
    55 #endif
    56 #endif /* __linux __ */
    57 #endif /* !SDL_BYTEORDER */
    58 
    59 
    60 #include "begin_code.h"
    61 /* Set up for C function definitions, even when using C++ */
    62 #ifdef __cplusplus
    63 /* *INDENT-OFF* */
    64 extern "C" {
    65 /* *INDENT-ON* */
    66 #endif
    67 
    68 /**
    69  *  \file SDL_endian.h
    70  *  
    71  *  Uses inline functions for compilers that support them, and static
    72  *  functions for those that do not.  Because these functions become
    73  *  static for compilers that do not support inline functions, this
    74  *  header should only be included in files that actually use them.
    75  */
    76 #if defined(__GNUC__) && defined(__i386__) && \
    77    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
    78 static __inline__ Uint16
    79 SDL_Swap16(Uint16 x)
    80 {
    81   __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
    82     return x;
    83 }
    84 #elif defined(__GNUC__) && defined(__x86_64__)
    85 static __inline__ Uint16
    86 SDL_Swap16(Uint16 x)
    87 {
    88   __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
    89     return x;
    90 }
    91 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
    92 static __inline__ Uint16
    93 SDL_Swap16(Uint16 x)
    94 {
    95     Uint16 result;
    96 
    97   __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
    98     return result;
    99 }
   100 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
   101 static __inline__ Uint16
   102 SDL_Swap16(Uint16 x)
   103 {
   104   __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
   105     return x;
   106 }
   107 #else
   108 static __inline__ Uint16
   109 SDL_Swap16(Uint16 x)
   110 {
   111     return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
   112 }
   113 #endif
   114 
   115 #if defined(__GNUC__) && defined(__i386__)
   116 static __inline__ Uint32
   117 SDL_Swap32(Uint32 x)
   118 {
   119   __asm__("bswap %0": "=r"(x):"0"(x));
   120     return x;
   121 }
   122 #elif defined(__GNUC__) && defined(__x86_64__)
   123 static __inline__ Uint32
   124 SDL_Swap32(Uint32 x)
   125 {
   126   __asm__("bswapl %0": "=r"(x):"0"(x));
   127     return x;
   128 }
   129 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
   130 static __inline__ Uint32
   131 SDL_Swap32(Uint32 x)
   132 {
   133     Uint32 result;
   134 
   135   __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
   136   __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
   137   __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
   138     return result;
   139 }
   140 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
   141 static __inline__ Uint32
   142 SDL_Swap32(Uint32 x)
   143 {
   144   __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
   145     return x;
   146 }
   147 #else
   148 static __inline__ Uint32
   149 SDL_Swap32(Uint32 x)
   150 {
   151     return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
   152                                     ((x >> 8) & 0x0000FF00) | (x >> 24)));
   153 }
   154 #endif
   155 
   156 #ifdef SDL_HAS_64BIT_TYPE
   157 #if defined(__GNUC__) && defined(__i386__)
   158 static __inline__ Uint64
   159 SDL_Swap64(Uint64 x)
   160 {
   161     union
   162     {
   163         struct
   164         {
   165             Uint32 a, b;
   166         } s;
   167         Uint64 u;
   168     } v;
   169     v.u = x;
   170   __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
   171             "1"(v.s.
   172                 b));
   173     return v.u;
   174 }
   175 #elif defined(__GNUC__) && defined(__x86_64__)
   176 static __inline__ Uint64
   177 SDL_Swap64(Uint64 x)
   178 {
   179   __asm__("bswapq %0": "=r"(x):"0"(x));
   180     return x;
   181 }
   182 #else
   183 static __inline__ Uint64
   184 SDL_Swap64(Uint64 x)
   185 {
   186     Uint32 hi, lo;
   187 
   188     /* Separate into high and low 32-bit values and swap them */
   189     lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   190     x >>= 32;
   191     hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
   192     x = SDL_Swap32(lo);
   193     x <<= 32;
   194     x |= SDL_Swap32(hi);
   195     return (x);
   196 }
   197 #endif
   198 #else
   199 /**
   200  *  This is mainly to keep compilers from complaining in SDL code.
   201  *  If there is no real 64-bit datatype, then compilers will complain about
   202  *  the fake 64-bit datatype that SDL provides when it compiles user code.
   203  */
   204 #define SDL_Swap64(X)	(X)
   205 #endif /* SDL_HAS_64BIT_TYPE */
   206 
   207 
   208 static __inline__ float
   209 SDL_SwapFloat(float x)
   210 {
   211     union
   212     {
   213         float f;
   214         Uint32 ui32;
   215     } swapper;
   216     swapper.f = x;
   217     swapper.ui32 = SDL_Swap32(swapper.ui32);
   218     return swapper.f;
   219 }
   220 
   221 
   222 /**
   223  *  \name Swap to native
   224  *  Byteswap item from the specified endianness to the native endianness.
   225  */
   226 /*@{*/
   227 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   228 #define SDL_SwapLE16(X)	(X)
   229 #define SDL_SwapLE32(X)	(X)
   230 #define SDL_SwapLE64(X)	(X)
   231 #define SDL_SwapFloatLE(X)	(X)
   232 #define SDL_SwapBE16(X)	SDL_Swap16(X)
   233 #define SDL_SwapBE32(X)	SDL_Swap32(X)
   234 #define SDL_SwapBE64(X)	SDL_Swap64(X)
   235 #define SDL_SwapFloatBE(X)	SDL_SwapFloat(X)
   236 #else
   237 #define SDL_SwapLE16(X)	SDL_Swap16(X)
   238 #define SDL_SwapLE32(X)	SDL_Swap32(X)
   239 #define SDL_SwapLE64(X)	SDL_Swap64(X)
   240 #define SDL_SwapFloatLE(X)	SDL_SwapFloat(X)
   241 #define SDL_SwapBE16(X)	(X)
   242 #define SDL_SwapBE32(X)	(X)
   243 #define SDL_SwapBE64(X)	(X)
   244 #define SDL_SwapFloatBE(X)	(X)
   245 #endif
   246 /*@}*//*Swap to native*/
   247 
   248 /* Ends C function definitions when using C++ */
   249 #ifdef __cplusplus
   250 /* *INDENT-OFF* */
   251 }
   252 /* *INDENT-ON* */
   253 #endif
   254 #include "close_code.h"
   255 
   256 #endif /* _SDL_endian_h */
   257 
   258 /* vi: set ts=4 sw=4 expandtab: */