mirror of
https://github.com/RetroDECK/Duckstation.git
synced 2024-11-23 14:25:37 +00:00
261 lines
6.3 KiB
C
261 lines
6.3 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2019 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/**
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* \file SDL_endian.h
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*
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* Functions for reading and writing endian-specific values
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*/
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#ifndef SDL_endian_h_
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#define SDL_endian_h_
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#include "SDL_stdinc.h"
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/**
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* \name The two types of endianness
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*/
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/* @{ */
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#define SDL_LIL_ENDIAN 1234
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#define SDL_BIG_ENDIAN 4321
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/* @} */
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#ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
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#ifdef __linux__
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#include <endian.h>
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#define SDL_BYTEORDER __BYTE_ORDER
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#else /* __linux__ */
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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
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#define SDL_BYTEORDER SDL_LIL_ENDIAN
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#endif
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#endif /* __linux__ */
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#endif /* !SDL_BYTEORDER */
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#include "begin_code.h"
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* \file SDL_endian.h
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*/
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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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SDL_FORCE_INLINE Uint16
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SDL_Swap16(Uint16 x)
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{
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__asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
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return x;
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}
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#elif defined(__GNUC__) && defined(__x86_64__)
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SDL_FORCE_INLINE Uint16
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SDL_Swap16(Uint16 x)
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{
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__asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
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return x;
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}
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#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
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SDL_FORCE_INLINE Uint16
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SDL_Swap16(Uint16 x)
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{
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int result;
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__asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
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return (Uint16)result;
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}
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#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
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SDL_FORCE_INLINE Uint16
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SDL_Swap16(Uint16 x)
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{
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__asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
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return x;
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}
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#elif defined(__WATCOMC__) && defined(__386__)
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extern _inline Uint16 SDL_Swap16(Uint16);
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#pragma aux SDL_Swap16 = \
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"xchg al, ah" \
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parm [ax] \
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modify [ax];
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#else
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SDL_FORCE_INLINE Uint16
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SDL_Swap16(Uint16 x)
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{
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return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
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}
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#endif
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#if defined(__GNUC__) && defined(__i386__)
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SDL_FORCE_INLINE Uint32
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SDL_Swap32(Uint32 x)
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{
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__asm__("bswap %0": "=r"(x):"0"(x));
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return x;
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}
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#elif defined(__GNUC__) && defined(__x86_64__)
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SDL_FORCE_INLINE Uint32
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SDL_Swap32(Uint32 x)
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{
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__asm__("bswapl %0": "=r"(x):"0"(x));
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return x;
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}
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#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
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SDL_FORCE_INLINE Uint32
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SDL_Swap32(Uint32 x)
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{
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Uint32 result;
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__asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
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__asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
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__asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
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return result;
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}
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#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
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SDL_FORCE_INLINE Uint32
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SDL_Swap32(Uint32 x)
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{
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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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}
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#elif defined(__WATCOMC__) && defined(__386__)
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extern _inline Uint32 SDL_Swap32(Uint32);
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#ifndef __SW_3 /* 486+ */
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#pragma aux SDL_Swap32 = \
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"bswap eax" \
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parm [eax] \
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modify [eax];
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#else /* 386-only */
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#pragma aux SDL_Swap32 = \
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"xchg al, ah" \
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"ror eax, 16" \
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"xchg al, ah" \
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parm [eax] \
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modify [eax];
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#endif
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#else
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SDL_FORCE_INLINE Uint32
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SDL_Swap32(Uint32 x)
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{
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return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
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((x >> 8) & 0x0000FF00) | (x >> 24)));
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}
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#endif
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#if defined(__GNUC__) && defined(__i386__)
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SDL_FORCE_INLINE Uint64
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SDL_Swap64(Uint64 x)
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{
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union
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{
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struct
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{
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Uint32 a, b;
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} s;
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Uint64 u;
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} v;
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v.u = x;
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__asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
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"1"(v.s.
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b));
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return v.u;
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}
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#elif defined(__GNUC__) && defined(__x86_64__)
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SDL_FORCE_INLINE Uint64
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SDL_Swap64(Uint64 x)
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{
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__asm__("bswapq %0": "=r"(x):"0"(x));
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return x;
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}
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#else
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SDL_FORCE_INLINE Uint64
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SDL_Swap64(Uint64 x)
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{
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Uint32 hi, lo;
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/* 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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x >>= 32;
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hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
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x = SDL_Swap32(lo);
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x <<= 32;
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x |= SDL_Swap32(hi);
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return (x);
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}
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#endif
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SDL_FORCE_INLINE float
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SDL_SwapFloat(float x)
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{
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union
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{
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float f;
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Uint32 ui32;
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} swapper;
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swapper.f = x;
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swapper.ui32 = SDL_Swap32(swapper.ui32);
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return swapper.f;
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}
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/**
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* \name Swap to native
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* Byteswap item from the specified endianness to the native endianness.
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*/
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/* @{ */
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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#define SDL_SwapLE16(X) (X)
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#define SDL_SwapLE32(X) (X)
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#define SDL_SwapLE64(X) (X)
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#define SDL_SwapFloatLE(X) (X)
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#define SDL_SwapBE16(X) SDL_Swap16(X)
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#define SDL_SwapBE32(X) SDL_Swap32(X)
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#define SDL_SwapBE64(X) SDL_Swap64(X)
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#define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
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#else
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#define SDL_SwapLE16(X) SDL_Swap16(X)
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#define SDL_SwapLE32(X) SDL_Swap32(X)
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#define SDL_SwapLE64(X) SDL_Swap64(X)
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#define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
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#define SDL_SwapBE16(X) (X)
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#define SDL_SwapBE32(X) (X)
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#define SDL_SwapBE64(X) (X)
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#define SDL_SwapFloatBE(X) (X)
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#endif
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/* @} *//* Swap to native */
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include "close_code.h"
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#endif /* SDL_endian_h_ */
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/* vi: set ts=4 sw=4 expandtab: */
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