SDL_endian.h
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上传日期:2022-06-22
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- /*
- SDL - Simple DirectMedia Layer
- Copyright (C) 1997-2006 Sam Lantinga
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- 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
- Lesser General Public License for more details.
- 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
- Sam Lantinga
- slouken@libsdl.org
- */
- /* Functions for reading and writing endian-specific values */
- #ifndef _SDL_endian_h
- #define _SDL_endian_h
- #include "SDL_stdinc.h"
- /* The two types of endianness */
- #define SDL_LIL_ENDIAN 1234
- #define SDL_BIG_ENDIAN 4321
- #ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
- #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 /* !SDL_BYTEORDER */
- #include "begin_code.h"
- /* Set up for C function definitions, even when using C++ */
- #ifdef __cplusplus
- extern "C" {
- #endif
- /* 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.
- */
- #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__))
- 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((x<<8)|(x>>8));
- }
- #endif
- #if defined(__GNUC__) && defined(__i386__) &&
- !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
- 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__))
- static __inline__ Uint32 SDL_Swap32(Uint32 x)
- {
- __asm__("rorw #8,%0ntswap %0ntrorw #8,%0" : "=d" (x) : "0" (x) : "cc");
- return x;
- }
- #else
- static __inline__ Uint32 SDL_Swap32(Uint32 x) {
- return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));
- }
- #endif
- #ifdef SDL_HAS_64BIT_TYPE
- #if defined(__GNUC__) && defined(__i386__) &&
- !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
- 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 = (Uint32)(x&0xFFFFFFFF);
- x >>= 32;
- hi = (Uint32)(x&0xFFFFFFFF);
- x = SDL_Swap32(lo);
- x <<= 32;
- x |= SDL_Swap32(hi);
- return(x);
- }
- #endif
- #else
- /* This is mainly to keep compilers from complaining in SDL code.
- 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.
- */
- #define SDL_Swap64(X) (X)
- #endif /* SDL_HAS_64BIT_TYPE */
- /* 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_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
- /* Ends C function definitions when using C++ */
- #ifdef __cplusplus
- }
- #endif
- #include "close_code.h"
- #endif /* _SDL_endian_h */