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  1. /*
  2.     SDL - Simple DirectMedia Layer
  3.     Copyright (C) 1997-2009 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.  *  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. /** @name SDL_ENDIANs
  34.  *  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. #if defined(__hppa__) || \
  43.     defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
  44.     (defined(__MIPS__) && defined(__MISPEB__)) || \
  45.     defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
  46.     defined(__sparc__)
  47. #define SDL_BYTEORDER   SDL_BIG_ENDIAN
  48. #else
  49. #define SDL_BYTEORDER   SDL_LIL_ENDIAN
  50. #endif
  51. #endif /* !SDL_BYTEORDER */
  52.  
  53.  
  54. #include "begin_code.h"
  55. /* Set up for C function definitions, even when using C++ */
  56. #ifdef __cplusplus
  57. extern "C" {
  58. #endif
  59.  
  60. /**
  61.  *  @name SDL_Swap Functions
  62.  *  Use inline functions for compilers that support them, and static
  63.  *  functions for those that do not.  Because these functions become
  64.  *  static for compilers that do not support inline functions, this
  65.  *  header should only be included in files that actually use them.
  66.  */
  67. /*@{*/
  68. #if defined(__GNUC__) && defined(__i386__) && \
  69.    !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
  70. static __inline__ Uint16 SDL_Swap16(Uint16 x)
  71. {
  72.         __asm__("xchgb %b0,%h0" : "=q" (x) :  "0" (x));
  73.         return x;
  74. }
  75. #elif defined(__GNUC__) && defined(__x86_64__)
  76. static __inline__ Uint16 SDL_Swap16(Uint16 x)
  77. {
  78.         __asm__("xchgb %b0,%h0" : "=Q" (x) :  "0" (x));
  79.         return x;
  80. }
  81. #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
  82. static __inline__ Uint16 SDL_Swap16(Uint16 x)
  83. {
  84.         Uint16 result;
  85.  
  86.         __asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));
  87.         return result;
  88. }
  89. #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
  90. static __inline__ Uint16 SDL_Swap16(Uint16 x)
  91. {
  92.         __asm__("rorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
  93.         return x;
  94. }
  95. #else
  96. static __inline__ Uint16 SDL_Swap16(Uint16 x) {
  97.         return((x<<8)|(x>>8));
  98. }
  99. #endif
  100.  
  101. #if defined(__GNUC__) && defined(__i386__) && \
  102.    !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
  103. static __inline__ Uint32 SDL_Swap32(Uint32 x)
  104. {
  105.         __asm__("bswap %0" : "=r" (x) : "0" (x));
  106.         return x;
  107. }
  108. #elif defined(__GNUC__) && defined(__x86_64__)
  109. static __inline__ Uint32 SDL_Swap32(Uint32 x)
  110. {
  111.         __asm__("bswapl %0" : "=r" (x) : "0" (x));
  112.         return x;
  113. }
  114. #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
  115. static __inline__ Uint32 SDL_Swap32(Uint32 x)
  116. {
  117.         Uint32 result;
  118.  
  119.         __asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));
  120.         __asm__("rlwimi %0,%2,8,8,15"   : "=&r" (result) : "0" (result),    "r" (x));
  121.         __asm__("rlwimi %0,%2,24,0,7"   : "=&r" (result) : "0" (result),    "r" (x));
  122.         return result;
  123. }
  124. #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
  125. static __inline__ Uint32 SDL_Swap32(Uint32 x)
  126. {
  127.         __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
  128.         return x;
  129. }
  130. #else
  131. static __inline__ Uint32 SDL_Swap32(Uint32 x) {
  132.         return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));
  133. }
  134. #endif
  135.  
  136. #ifdef SDL_HAS_64BIT_TYPE
  137. #if defined(__GNUC__) && defined(__i386__) && \
  138.    !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
  139. static __inline__ Uint64 SDL_Swap64(Uint64 x)
  140. {
  141.         union {
  142.                 struct { Uint32 a,b; } s;
  143.                 Uint64 u;
  144.         } v;
  145.         v.u = x;
  146.         __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
  147.                 : "=r" (v.s.a), "=r" (v.s.b)
  148.                 : "0" (v.s.a), "1" (v.s.b));
  149.         return v.u;
  150. }
  151. #elif defined(__GNUC__) && defined(__x86_64__)
  152. static __inline__ Uint64 SDL_Swap64(Uint64 x)
  153. {
  154.         __asm__("bswapq %0" : "=r" (x) : "0" (x));
  155.         return x;
  156. }
  157. #else
  158. static __inline__ Uint64 SDL_Swap64(Uint64 x)
  159. {
  160.         Uint32 hi, lo;
  161.  
  162.         /* Separate into high and low 32-bit values and swap them */
  163.         lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
  164.         x >>= 32;
  165.         hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
  166.         x = SDL_Swap32(lo);
  167.         x <<= 32;
  168.         x |= SDL_Swap32(hi);
  169.         return(x);
  170. }
  171. #endif
  172. #else
  173. /* This is mainly to keep compilers from complaining in SDL code.
  174.  * If there is no real 64-bit datatype, then compilers will complain about
  175.  * the fake 64-bit datatype that SDL provides when it compiles user code.
  176.  */
  177. #define SDL_Swap64(X)   (X)
  178. #endif /* SDL_HAS_64BIT_TYPE */
  179. /*@}*/
  180.  
  181. /**
  182.  *  @name SDL_SwapLE and SDL_SwapBE Functions
  183.  *  Byteswap item from the specified endianness to the native endianness
  184.  */
  185. /*@{*/
  186. #if SDL_BYTEORDER == SDL_LIL_ENDIAN
  187. #define SDL_SwapLE16(X) (X)
  188. #define SDL_SwapLE32(X) (X)
  189. #define SDL_SwapLE64(X) (X)
  190. #define SDL_SwapBE16(X) SDL_Swap16(X)
  191. #define SDL_SwapBE32(X) SDL_Swap32(X)
  192. #define SDL_SwapBE64(X) SDL_Swap64(X)
  193. #else
  194. #define SDL_SwapLE16(X) SDL_Swap16(X)
  195. #define SDL_SwapLE32(X) SDL_Swap32(X)
  196. #define SDL_SwapLE64(X) SDL_Swap64(X)
  197. #define SDL_SwapBE16(X) (X)
  198. #define SDL_SwapBE32(X) (X)
  199. #define SDL_SwapBE64(X) (X)
  200. #endif
  201. /*@}*/
  202.  
  203. /* Ends C function definitions when using C++ */
  204. #ifdef __cplusplus
  205. }
  206. #endif
  207. #include "close_code.h"
  208.  
  209. #endif /* _SDL_endian_h */
  210.