include/SDL_endian.h
author Sam Lantinga <slouken@libsdl.org>
Mon, 06 Mar 2006 16:33:23 +0000
changeset 1474 351d757c7edd
parent 1469 bf867c1e57e3
child 1475 d45aefcac017
permissions -rw-r--r--
Maybe it's easier to collect the big-endian architectures. :)
     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(__hppa__) || \
    36     defined(__m68k__) || defined(mc68000) || \
    37     (defined(__MIPS__) && defined(__MISPEB__)) || \
    38     defined(__ppc__) || defined(__POWERPC__) || \
    39     defined(__sparc__)
    40 #define SDL_BYTEORDER	SDL_BIG_ENDIAN
    41 #else
    42 #define SDL_BYTEORDER	SDL_LIL_ENDIAN
    43 #endif
    44 #endif /* !SDL_BYTEORDER */
    45 
    46 
    47 #include "begin_code.h"
    48 /* Set up for C function definitions, even when using C++ */
    49 #ifdef __cplusplus
    50 extern "C" {
    51 #endif
    52 
    53 /* Use inline functions for compilers that support them, and static
    54    functions for those that do not.  Because these functions become
    55    static for compilers that do not support inline functions, this
    56    header should only be included in files that actually use them.
    57 */
    58 #if defined(__GNUC__) && defined(__i386__) && \
    59    !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
    60 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    61 {
    62 	__asm__("xchgb %b0,%h0" : "=q" (x) :  "0" (x));
    63 	return x;
    64 }
    65 #elif defined(__GNUC__) && defined(__x86_64__)
    66 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    67 {
    68 	__asm__("xchgb %b0,%h0" : "=Q" (x) :  "0" (x));
    69 	return x;
    70 }
    71 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
    72 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    73 {
    74 	Uint16 result;
    75 
    76 	__asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));
    77 	return result;
    78 }
    79 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
    80 static __inline__ Uint16 SDL_Swap16(Uint16 x)
    81 {
    82 	__asm__("rorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
    83 	return x;
    84 }
    85 #else
    86 static __inline__ Uint16 SDL_Swap16(Uint16 x) {
    87 	return((x<<8)|(x>>8));
    88 }
    89 #endif
    90 
    91 #if defined(__GNUC__) && defined(__i386__)
    92 static __inline__ Uint32 SDL_Swap32(Uint32 x)
    93 {
    94 	__asm__("bswap %0" : "=r" (x) : "0" (x));
    95 	return x;
    96 }
    97 #elif defined(__GNUC__) && defined(__x86_64__)
    98 static __inline__ Uint32 SDL_Swap32(Uint32 x)
    99 {
   100 	__asm__("bswapl %0" : "=r" (x) : "0" (x));
   101 	return x;
   102 }
   103 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
   104 static __inline__ Uint32 SDL_Swap32(Uint32 x)
   105 {
   106 	Uint32 result;
   107 
   108 	__asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));
   109 	__asm__("rlwimi %0,%2,8,8,15"   : "=&r" (result) : "0" (result),    "r" (x));
   110 	__asm__("rlwimi %0,%2,24,0,7"   : "=&r" (result) : "0" (result),    "r" (x));
   111 	return result;
   112 }
   113 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
   114 static __inline__ Uint32 SDL_Swap32(Uint32 x)
   115 {
   116 	__asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) :  "0" (x) : "cc");
   117 	return x;
   118 }
   119 #else
   120 static __inline__ Uint32 SDL_Swap32(Uint32 x) {
   121 	return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));
   122 }
   123 #endif
   124 
   125 #ifdef SDL_HAS_64BIT_TYPE
   126 #if defined(__GNUC__) && defined(__i386__)
   127 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   128 {
   129 	union { 
   130 		struct { Uint32 a,b; } s;
   131 		Uint64 u;
   132 	} v;
   133 	v.u = x;
   134 	__asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1" 
   135 	        : "=r" (v.s.a), "=r" (v.s.b) 
   136 	        : "0" (v.s.a), "1" (v.s.b)); 
   137 	return v.u;
   138 }
   139 #elif defined(__GNUC__) && defined(__x86_64__)
   140 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   141 {
   142 	__asm__("bswapq %0" : "=r" (x) : "0" (x));
   143 	return x;
   144 }
   145 #else
   146 static __inline__ Uint64 SDL_Swap64(Uint64 x)
   147 {
   148 	Uint32 hi, lo;
   149 
   150 	/* Separate into high and low 32-bit values and swap them */
   151 	lo = (Uint32)(x&0xFFFFFFFF);
   152 	x >>= 32;
   153 	hi = (Uint32)(x&0xFFFFFFFF);
   154 	x = SDL_Swap32(lo);
   155 	x <<= 32;
   156 	x |= SDL_Swap32(hi);
   157 	return(x);
   158 }
   159 #endif
   160 #else
   161 /* This is mainly to keep compilers from complaining in SDL code.
   162    If there is no real 64-bit datatype, then compilers will complain about
   163    the fake 64-bit datatype that SDL provides when it compiles user code.
   164 */
   165 #define SDL_Swap64(X)	(X)
   166 #endif /* SDL_HAS_64BIT_TYPE */
   167 
   168 
   169 /* Byteswap item from the specified endianness to the native endianness */
   170 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
   171 #define SDL_SwapLE16(X)	(X)
   172 #define SDL_SwapLE32(X)	(X)
   173 #define SDL_SwapLE64(X)	(X)
   174 #define SDL_SwapBE16(X)	SDL_Swap16(X)
   175 #define SDL_SwapBE32(X)	SDL_Swap32(X)
   176 #define SDL_SwapBE64(X)	SDL_Swap64(X)
   177 #else
   178 #define SDL_SwapLE16(X)	SDL_Swap16(X)
   179 #define SDL_SwapLE32(X)	SDL_Swap32(X)
   180 #define SDL_SwapLE64(X)	SDL_Swap64(X)
   181 #define SDL_SwapBE16(X)	(X)
   182 #define SDL_SwapBE32(X)	(X)
   183 #define SDL_SwapBE64(X)	(X)
   184 #endif
   185 
   186 /* Ends C function definitions when using C++ */
   187 #ifdef __cplusplus
   188 }
   189 #endif
   190 #include "close_code.h"
   191 
   192 #endif /* _SDL_endian_h */