SDL_endian.h 5.8 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239
/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/**
 *  \file SDL_endian.h
 *
 *  Functions for reading and writing endian-specific values
 */

#ifndef _SDL_endian_h
#define _SDL_endian_h

#include "SDL_stdinc.h"

/**
 *  \name The two types of endianness
 */
/* @{ */
#define SDL_LIL_ENDIAN  1234
#define SDL_BIG_ENDIAN  4321
/* @} */

#ifndef SDL_BYTEORDER           /* Not defined in SDL_config.h? */
#ifdef __linux__
#include <endian.h>
#define SDL_BYTEORDER  __BYTE_ORDER
#else /* __linux__ */
#if defined(__hppa__) || \
    defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
    (defined(__MIPS__) && defined(__MISPEB__)) || \
    defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
    defined(__sparc__)
#define SDL_BYTEORDER   SDL_BIG_ENDIAN
#else
#define SDL_BYTEORDER   SDL_LIL_ENDIAN
#endif
#endif /* __linux__ */
#endif /* !SDL_BYTEORDER */


#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/**
 *  \file SDL_endian.h
 */
#if defined(__GNUC__) && defined(__i386__) && \
   !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
    int result;

  __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
    return (Uint16)result;
}
#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
    return x;
}
#else
SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)
{
    return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
}
#endif

#if defined(__GNUC__) && defined(__i386__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswap %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswapl %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
    Uint32 result;

  __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
  __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
  __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
    return result;
}
#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
    return x;
}
#else
SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)
{
    return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
                                    ((x >> 8) & 0x0000FF00) | (x >> 24)));
}
#endif

#if defined(__GNUC__) && defined(__i386__)
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
    union
    {
        struct
        {
            Uint32 a, b;
        } s;
        Uint64 u;
    } v;
    v.u = x;
  __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
            "1"(v.s.
                b));
    return v.u;
}
#elif defined(__GNUC__) && defined(__x86_64__)
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
  __asm__("bswapq %0": "=r"(x):"0"(x));
    return x;
}
#else
SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)
{
    Uint32 hi, lo;

    /* Separate into high and low 32-bit values and swap them */
    lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
    x >>= 32;
    hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
    x = SDL_Swap32(lo);
    x <<= 32;
    x |= SDL_Swap32(hi);
    return (x);
}
#endif


SDL_FORCE_INLINE float
SDL_SwapFloat(float x)
{
    union
    {
        float f;
        Uint32 ui32;
    } swapper;
    swapper.f = x;
    swapper.ui32 = SDL_Swap32(swapper.ui32);
    return swapper.f;
}


/**
 *  \name Swap to native
 *  Byteswap item from the specified endianness to the native endianness.
 */
/* @{ */
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
#define SDL_SwapLE16(X) (X)
#define SDL_SwapLE32(X) (X)
#define SDL_SwapLE64(X) (X)
#define SDL_SwapFloatLE(X)  (X)
#define SDL_SwapBE16(X) SDL_Swap16(X)
#define SDL_SwapBE32(X) SDL_Swap32(X)
#define SDL_SwapBE64(X) SDL_Swap64(X)
#define SDL_SwapFloatBE(X)  SDL_SwapFloat(X)
#else
#define SDL_SwapLE16(X) SDL_Swap16(X)
#define SDL_SwapLE32(X) SDL_Swap32(X)
#define SDL_SwapLE64(X) SDL_Swap64(X)
#define SDL_SwapFloatLE(X)  SDL_SwapFloat(X)
#define SDL_SwapBE16(X) (X)
#define SDL_SwapBE32(X) (X)
#define SDL_SwapBE64(X) (X)
#define SDL_SwapFloatBE(X)  (X)
#endif
/* @} *//* Swap to native */

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* _SDL_endian_h */

/* vi: set ts=4 sw=4 expandtab: */