1 /* 2 SDL - Simple DirectMedia Layer 3 Copyright (C) 1997-2004 Sam Lantinga 4 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. 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 Library General Public License for more details. 14 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 18 19 Sam Lantinga 20 slouken (at) libsdl.org 21 */ 22 23 #ifdef SAVE_RCSID 24 static char rcsid = 25 "@(#) $Id: SDL_endian.h,v 1.11 2004/11/27 23:11:20 pmandin Exp $"; 26 #endif 27 28 /* Functions for reading and writing endian-specific values */ 29 30 #ifndef _SDL_endian_h 31 #define _SDL_endian_h 32 33 /* These functions read and write data of the specified endianness, 34 dynamically translating to the host machine endianness. 35 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 */ 44 45 #include <stdio.h> 46 47 #include "SDL_types.h" 48 #include "SDL_rwops.h" 49 #include "SDL_byteorder.h" 50 51 #include "begin_code.h" 52 /* Set up for C function definitions, even when using C++ */ 53 #ifdef __cplusplus 54 extern "C" { 55 #endif 56 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; 78 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 93 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; 110 111 __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 127 128 #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; 152 153 /* 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 */ 170 171 172 /* 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 188 189 /* 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); 196 197 /* 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); 204 205 206 /* Ends C function definitions when using C++ */ 207 #ifdef __cplusplus 208 } 209 #endif 210 #include "close_code.h" 211 212 #endif /* _SDL_endian_h */ 213
