include/SDL_endian.h
author Sam Lantinga <slouken@libsdl.org>
Sat, 18 Feb 2006 07:05:18 +0000
changeset 1369 42eeb14770e3
parent 1368 533567cbb576
child 1372 3e171fa5f4df
permissions -rw-r--r--
Doh! Bitten by search and replace. :)
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 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 /* Functions for reading and writing endian-specific values */
    24 
    25 #ifndef _SDL_endian_h
    26 #define _SDL_endian_h
    27 
    28 #include "SDL_stdinc.h"
    29 
    30 /* The two types of endianness */
    31 #define SDL_LIL_ENDIAN	1234
    32 #define SDL_BIG_ENDIAN	4321
    33 
    34 #ifndef SDL_BYTEORDER	/* Not defined in SDL_config.h? */
    35 #if (defined(__i386__) || defined(__i386)) || \
    36      defined(__ia64__) || defined(__x86_64__) || \
    37     (defined(__alpha__) || defined(__alpha)) || \
    38     (defined(__arm__) || defined(__thumb__)) || \
    39     (defined(__sh__) || defined(__sh64__)) || \
    40     (defined(__mips__) && defined(__MIPSEL__)) || \
    41      defined(__SYMBIAN32__) || defined(__OS2__)
    42 #define SDL_BYTEORDER	SDL_LIL_ENDIAN
    43 #else
    44 #define SDL_BYTEORDER	SDL_BIG_ENDIAN
    45 #endif
    46 #endif /* !SDL_BYTEORDER */
    47 
    48 
    49 #include "begin_code.h"
    50 /* Set up for C function definitions, even when using C++ */
    51 #ifdef __cplusplus
    52 extern "C" {
    53 #endif
    54 
    55 /* Use inline functions for compilers that support them, and static
    56    functions for those that do not.  Because these functions become
    57    static for compilers that do not support inline functions, this
    58    header should only be included in files that actually use them.
    59 */
    60 #if defined(__GNUC__) && defined(__i386__) &&
    61    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
    62 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    63 {
    64 	__asm__("xchgb %b0,%h0" : "=q" (x) :  "0" (x));
    65 	return x;
    66 }
    67 #elif defined(__GNUC__) && defined(__x86_64__)
    68 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    69 {
    70 	__asm__("xchgb %b0,%h0" : "=Q" (x) :  "0" (x));
    71 	return x;
    72 }
    73 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
    74 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    75 {
    76 	Uint16 result;
    77 
    78 	__asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));
    79 	return result;
    80 }
    81 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
    82 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    83 {
    84 	__asm__("rorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
    85 	return x;
    86 }
    87 #else
    88 static __inline__ Uint16 SDL_Swap16(Uint16 x) {
    89 	return((x<<8)|(x>>8));
    90 }
    91 #endif
    92 
    93 #if defined(__GNUC__) && defined(__i386__)
    94 static __inline__ Uint32 SDL_Swap32(Uint32 x)
    95 {
    96 	__asm__("bswap %0" : "=r" (x) : "0" (x));
    97 	return x;
    98 }
    99 #elif defined(__GNUC__) && defined(__x86_64__)
   100 static __inline__ Uint32 SDL_Swap32(Uint32 x)
   101 {
   102 	__asm__("bswapl %0" : "=r" (x) : "0" (x));
   103 	return x;
   104 }
   105 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
   106 static __inline__ Uint32 SDL_Swap32(Uint32 x)
   107 {
   108 	Uint32 result;
   109 
   110 	__asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));
   111 	__asm__("rlwimi %0,%2,8,8,15"   : "=&r" (result) : "0" (result),    "r" (x));
   112 	__asm__("rlwimi %0,%2,24,0,7"   : "=&r" (result) : "0" (result),    "r" (x));
   113 	return result;
   114 }
   115 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
   116 static __inline__ Uint32 SDL_Swap32(Uint32 x)
   117 {
   118 	__asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
   119 	return x;
   120 }
   121 #else
   122 static __inline__ Uint32 SDL_Swap32(Uint32 x) {
   123 	return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));
   124 }
   125 #endif
   126 
   127 #ifdef SDL_HAS_64BIT_TYPE
   128 #if defined(__GNUC__) && defined(__i386__)
   129 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   130 {
   131 	union { 
   132 		struct { Uint32 a,b; } s;
   133 		Uint64 u;
   134 	} v;
   135 	v.u = x;
   136 	__asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1" 
   137 	        : "=r" (v.s.a), "=r" (v.s.b) 
   138 	        : "0" (v.s.a), "1" (v.s.b)); 
   139 	return v.u;
   140 }
   141 #elif defined(__GNUC__) && defined(__x86_64__)
   142 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   143 {
   144 	__asm__("bswapq %0" : "=r" (x) : "0" (x));
   145 	return x;
   146 }
   147 #else
   148 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   149 {
   150 	Uint32 hi, lo;
   151 
   152 	/* Separate into high and low 32-bit values and swap them */
   153 	lo = (Uint32)(x&0xFFFFFFFF);
   154 	x >>= 32;
   155 	hi = (Uint32)(x&0xFFFFFFFF);
   156 	x = SDL_Swap32(lo);
   157 	x <<= 32;
   158 	x |= SDL_Swap32(hi);
   159 	return(x);
   160 }
   161 #endif
   162 #else
   163 /* This is mainly to keep compilers from complaining in SDL code.
   164    If there is no real 64-bit datatype, then compilers will complain about
   165    the fake 64-bit datatype that SDL provides when it compiles user code.
   166 */
   167 #define SDL_Swap64(X)	(X)
   168 #endif /* SDL_HAS_64BIT_TYPE */
   169 
   170 
   171 /* Byteswap item from the specified endianness to the native endianness */
   172 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   173 #define SDL_SwapLE16(X)	(X)
   174 #define SDL_SwapLE32(X)	(X)
   175 #define SDL_SwapLE64(X)	(X)
   176 #define SDL_SwapBE16(X)	SDL_Swap16(X)
   177 #define SDL_SwapBE32(X)	SDL_Swap32(X)
   178 #define SDL_SwapBE64(X)	SDL_Swap64(X)
   179 #else
   180 #define SDL_SwapLE16(X)	SDL_Swap16(X)
   181 #define SDL_SwapLE32(X)	SDL_Swap32(X)
   182 #define SDL_SwapLE64(X)	SDL_Swap64(X)
   183 #define SDL_SwapBE16(X)	(X)
   184 #define SDL_SwapBE32(X)	(X)
   185 #define SDL_SwapBE64(X)	(X)
   186 #endif
   187 
   188 /* Ends C function definitions when using C++ */
   189 #ifdef __cplusplus
   190 }
   191 #endif
   192 #include "close_code.h"
   193 
   194 #endif /* _SDL_endian_h */