SDL: include/SDL_endian.h@aebfa3ce2a53

     1 /*

     2     SDL - Simple DirectMedia Layer

     3     Copyright (C) 1997-2004 Sam Lantinga

     5     This library is free software; you can redistribute it and/or

     6     modify it under the terms of the GNU Library General Public

     7     License as published by the Free Software Foundation; either

     8     version 2 of the License, or (at your option) any later version.

    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     Library General Public License for more details.

    15     You should have received a copy of the GNU Library General Public

    16     License along with this library; if not, write to the Free

    17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    19     Sam Lantinga

    20     slouken@libsdl.org

    21 */

    23 #ifdef SAVE_RCSID

    24 static char rcsid =

    25  "@(#) $Id$";

    26 #endif

    28 /* Functions for reading and writing endian-specific values */

    30 #ifndef _SDL_endian_h

    31 #define _SDL_endian_h

    33 /* These functions read and write data of the specified endianness,

    34    dynamically translating to the host machine endianness.

    36    e.g.: If you want to read a 16 bit value on big-endian machine from

    37          an open file containing little endian values, you would use:

    38 		value = SDL_ReadLE16(rp);

    39          Note that the read/write functions use SDL_RWops pointers

    40          instead of FILE pointers.  This allows you to read and write

    41          endian values from large chunks of memory as well as files

    42          and other data sources.

    43 */

    45 #include <stdio.h>

    47 #include "SDL_types.h"

    48 #include "SDL_rwops.h"

    49 #include "SDL_byteorder.h"

    51 #include "begin_code.h"

    52 /* Set up for C function definitions, even when using C++ */

    53 #ifdef __cplusplus

    54 extern "C" {

    55 #endif

    57 /* Use inline functions for compilers that support them, and static

    58    functions for those that do not.  Because these functions become

    59    static for compilers that do not support inline functions, this

    60    header should only be included in files that actually use them.

    61 */

    62 #if defined(__GNUC__) && defined(__i386__)

    63 static __inline__ Uint16 SDL_Swap16(Uint16 x)

    64 {

    65 	__asm__("xchgb %b0,%h0" : "=q" (x) :  "0" (x));

    66 	return x;

    67 }

    68 #elif defined(__GNUC__) && defined(__x86_64__)

    69 static __inline__ Uint16 SDL_Swap16(Uint16 x)

    70 {

    71 	__asm__("xchgb %b0,%h0" : "=Q" (x) :  "0" (x));

    72 	return x;

    73 }

    74 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))

    75 static __inline__ Uint16 SDL_Swap16(Uint16 x)

    76 {

    77 	Uint16 result;

    79 	__asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));

    80 	return result;

    81 }

    82 #elif defined(__GNUC__) && defined(__M68000__)

    83 static __inline__ Uint16 SDL_Swap16(Uint16 x)

    84 {

    85 	__asm__("rorw #8,%0" : "=d" (x) :  "0" (x) : "cc");

    86 	return x;

    87 }

    88 #else

    89 static __inline__ Uint16 SDL_Swap16(Uint16 x) {

    90 	return((x<<8)|(x>>8));

    91 }

    92 #endif

    94 #if defined(__GNUC__) && defined(__i386__)

    95 static __inline__ Uint32 SDL_Swap32(Uint32 x)

    96 {

    97 	__asm__("bswap %0" : "=r" (x) : "0" (x));

    98 	return x;

    99 }

   100 #elif defined(__GNUC__) && defined(__x86_64__)

   101 static __inline__ Uint32 SDL_Swap32(Uint32 x)

   102 {

   103 	__asm__("bswapl %0" : "=r" (x) : "0" (x));

   104 	return x;

   105 }

   106 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))

   107 static __inline__ Uint32 SDL_Swap32(Uint32 x)

   108 {

   109 	Uint32 result;

   111 	__asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));

   112 	__asm__("rlwimi %0,%2,8,8,15"   : "=&r" (result) : "0" (result),    "r" (x));

   113 	__asm__("rlwimi %0,%2,24,0,7"   : "=&r" (result) : "0" (result),    "r" (x));

   114 	return result;

   115 }

   116 #elif defined(__GNUC__) && defined(__M68000__)

   117 static __inline__ Uint32 SDL_Swap32(Uint32 x)

   118 {

   119 	__asm__("rorw	#8,%0\n\tswap	%0\n\tror	#8,%0" : "=d" (x) :  "0" (x) : "cc");

   120 	return x;

   121 }

   122 #else

   123 static __inline__ Uint32 SDL_Swap32(Uint32 x) {

   124 	return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));

   125 }

   126 #endif

   128 #ifdef SDL_HAS_64BIT_TYPE

   129 #if defined(__GNUC__) && defined(__i386__)

   130 static __inline__ Uint64 SDL_Swap64(Uint64 x)

   131 {

   132 	union {

   133 		struct { Uint32 a,b; } s;

   134 		Uint64 u;

   135 	} v;

   136 	v.u = x;

   137 	__asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"

   138 	        : "=r" (v.s.a), "=r" (v.s.b)

   139 	        : "0" (v.s.a), "1" (v.s.b));

   140 	return v.u;

   141 }

   142 #elif defined(__GNUC__) && defined(__x86_64__)

   143 static __inline__ Uint64 SDL_Swap64(Uint64 x)

   144 {

   145 	__asm__("bswapq %0" : "=r" (x) : "0" (x));

   146 	return x;

   147 }

   148 #else

   149 static __inline__ Uint64 SDL_Swap64(Uint64 x)

   150 {

   151 	Uint32 hi, lo;

   153 	/* Separate into high and low 32-bit values and swap them */

   154 	lo = (Uint32)(x&0xFFFFFFFF);

   155 	x >>= 32;

   156 	hi = (Uint32)(x&0xFFFFFFFF);

   157 	x = SDL_Swap32(lo);

   158 	x <<= 32;

   159 	x |= SDL_Swap32(hi);

   160 	return(x);

   161 }

   162 #endif

   163 #else

   164 /* This is mainly to keep compilers from complaining in SDL code.

   165    If there is no real 64-bit datatype, then compilers will complain about

   166    the fake 64-bit datatype that SDL provides when it compiles user code.

   167 */

   168 #define SDL_Swap64(X)	(X)

   169 #endif /* SDL_HAS_64BIT_TYPE */

   172 /* Byteswap item from the specified endianness to the native endianness */

   173 #if SDL_BYTEORDER == SDL_LIL_ENDIAN

   174 #define SDL_SwapLE16(X)	(X)

   175 #define SDL_SwapLE32(X)	(X)

   176 #define SDL_SwapLE64(X)	(X)

   177 #define SDL_SwapBE16(X)	SDL_Swap16(X)

   178 #define SDL_SwapBE32(X)	SDL_Swap32(X)

   179 #define SDL_SwapBE64(X)	SDL_Swap64(X)

   180 #else

   181 #define SDL_SwapLE16(X)	SDL_Swap16(X)

   182 #define SDL_SwapLE32(X)	SDL_Swap32(X)

   183 #define SDL_SwapLE64(X)	SDL_Swap64(X)

   184 #define SDL_SwapBE16(X)	(X)

   185 #define SDL_SwapBE32(X)	(X)

   186 #define SDL_SwapBE64(X)	(X)

   187 #endif

   189 /* Read an item of the specified endianness and return in native format */

   190 extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);

   191 extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);

   192 extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);

   193 extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);

   194 extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);

   195 extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);

   197 /* Write an item of native format to the specified endianness */

   198 extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);

   199 extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);

   200 extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);

   201 extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);

   202 extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);

   203 extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);

   206 /* Ends C function definitions when using C++ */

   207 #ifdef __cplusplus

   208 }

   209 #endif

   210 #include "close_code.h"

   212 #endif /* _SDL_endian_h */

author	Sam Lantinga <slouken@libsdl.org>
	Tue, 25 Jan 2005 17:58:44 +0000
changeset 1033	aebfa3ce2a53
parent 1031	3cf036d8861f
child 1044	d36ea7925763
permissions	-rw-r--r--