SDL_endian.h

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2011 Sam Lantinga <[email protected]>

  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
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif

/**
 *  \file SDL_endian.h
 *  
 *  Uses inline functions for compilers that support them, and static
 *  functions for those that do not.  Because these functions become
 *  static for compilers that do not support inline functions, this
 *  header should only be included in files that actually use them.
 */
#if defined(__GNUC__) && defined(__i386__) && \
   !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
static __inline__ Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint16
SDL_Swap16(Uint16 x)
{
  __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
static __inline__ Uint16
SDL_Swap16(Uint16 x)
{
    Uint16 result;

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

#if defined(__GNUC__) && defined(__i386__)
static __inline__ Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswap %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint32
SDL_Swap32(Uint32 x)
{
  __asm__("bswapl %0": "=r"(x):"0"(x));
    return x;
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
static __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__)
static __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
static __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__)
static __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__)
static __inline__ Uint64
SDL_Swap64(Uint64 x)
{
  __asm__("bswapq %0": "=r"(x):"0"(x));
    return x;
}
#else
static __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


static __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
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"

#endif /* _SDL_endian_h */

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