SDL_endian.h
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2009 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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/**
* @file SDL_endian.h
* Functions for reading and writing endian-specific values
*/
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#ifndef _SDL_endian_h
#define _SDL_endian_h
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#include "SDL_stdinc.h"
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#define SDL_LIL_ENDIAN 1234
#define SDL_BIG_ENDIAN 4321
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#ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
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#if defined(__hppa__) || \
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defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
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(defined(__MIPS__) && defined(__MISPEB__)) || \
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defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
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defined(__sparc__)
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#define SDL_BYTEORDER SDL_BIG_ENDIAN
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#else
#define SDL_BYTEORDER SDL_LIL_ENDIAN
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#endif
#endif /* !SDL_BYTEORDER */
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#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif
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/**
* @name SDL_Swap Functions
* Use 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.
*/
/*@{*/
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#if defined(__GNUC__) && defined(__i386__) && \
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!(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
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static __inline__ Uint16 SDL_Swap16(Uint16 x)
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__asm__("xchgb %b0,%h0" : "=q" (x) : "0" (x));
return x;
}
#elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint16 SDL_Swap16(Uint16 x)
{
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__asm__("xchgb %b0,%h0" : "=Q" (x) : "0" (x));
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return x;
}
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#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
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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;
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#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
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static __inline__ Uint16 SDL_Swap16(Uint16 x)
{
__asm__("rorw #8,%0" : "=d" (x) : "0" (x) : "cc");
return x;
}
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static __inline__ Uint16 SDL_Swap16(Uint16 x) {
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return SDL_static_cast(Uint16, ((x<<8)|(x>>8)));
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}
#endif
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#if defined(__GNUC__) && defined(__i386__) && \
!(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
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static __inline__ Uint32 SDL_Swap32(Uint32 x)
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__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;
}
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#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
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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;
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#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
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static __inline__ Uint32 SDL_Swap32(Uint32 x)
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__asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) : "0" (x) : "cc");
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return x;
}
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static __inline__ Uint32 SDL_Swap32(Uint32 x) {
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return SDL_static_cast(Uint32, ((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24)));
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}
#endif
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#ifdef SDL_HAS_64BIT_TYPE
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#if defined(__GNUC__) && defined(__i386__) && \
!(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
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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)
{
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Uint32 hi, lo;
/* Separate into high and low 32-bit values and swap them */
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lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
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hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
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x = SDL_Swap32(lo);
x <<= 32;
x |= SDL_Swap32(hi);
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return (x);
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}
#endif
#else
/* This is mainly to keep compilers from complaining in SDL code.
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* If there is no real 64-bit datatype, then compilers will complain about
* the fake 64-bit datatype that SDL provides when it compiles user code.
*/
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#define SDL_Swap64(X) (X)
#endif /* SDL_HAS_64BIT_TYPE */
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/**
* @name SDL_SwapLE and SDL_SwapBE Functions
* Byteswap item from the specified endianness to the native endianness
*/
/*@{*/
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
#define SDL_SwapLE16(X) (X)
#define SDL_SwapLE32(X) (X)
#define SDL_SwapLE64(X) (X)
#define SDL_SwapBE16(X) SDL_Swap16(X)
#define SDL_SwapBE32(X) SDL_Swap32(X)
#define SDL_SwapBE64(X) SDL_Swap64(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_SwapBE16(X) (X)
#define SDL_SwapBE32(X) (X)
#define SDL_SwapBE64(X) (X)
#endif
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/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"
#endif /* _SDL_endian_h */