1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2012 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22
23 /**
24 * @file SDL_endian.h
25 * Functions for reading and writing endian-specific values
26 */
27
28 #ifndef _SDL_endian_h
29 #define _SDL_endian_h
30
31 #include "SDL_stdinc.h"
32
33 /** @name SDL_ENDIANs
34 * The two types of endianness
35 */
36 /*@{*/
37 #define SDL_LIL_ENDIAN 1234
38 #define SDL_BIG_ENDIAN 4321
39 /*@}*/
40
41 #ifndef SDL_BYTEORDER /* Not defined in SDL_config.h? */
42 #ifdef __linux__
43 #include <endian.h>
44 #define SDL_BYTEORDER __BYTE_ORDER
45 #else /* __linux __ */
46 #if defined(__hppa__) || \
47 defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
48 (defined(__MIPS__) && defined(__MISPEB__)) || \
49 defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
50 defined(__sparc__)
51 #define SDL_BYTEORDER SDL_BIG_ENDIAN
52 #else
53 #define SDL_BYTEORDER SDL_LIL_ENDIAN
54 #endif
55 #endif /* __linux __ */
56 #endif /* !SDL_BYTEORDER */
57
58
59 #include "begin_code.h"
60 /* Set up for C function definitions, even when using C++ */
61 #ifdef __cplusplus
62 extern "C" {
63 #endif
64
65 /**
66 * @name SDL_Swap Functions
67 * Use inline functions for compilers that support them, and static
68 * functions for those that do not. Because these functions become
69 * static for compilers that do not support inline functions, this
70 * header should only be included in files that actually use them.
71 */
72 /*@{*/
73 #if defined(__GNUC__) && defined(__i386__) && \
74 !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
SDL_Swap16(Uint16 x)75 static __inline__ Uint16 SDL_Swap16(Uint16 x)
76 {
77 __asm__("xchgb %b0,%h0" : "=q" (x) : "0" (x));
78 return x;
79 }
80 #elif defined(__GNUC__) && defined(__x86_64__)
81 static __inline__ Uint16 SDL_Swap16(Uint16 x)
82 {
83 __asm__("xchgb %b0,%h0" : "=Q" (x) : "0" (x));
84 return x;
85 }
86 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
87 static __inline__ Uint16 SDL_Swap16(Uint16 x)
88 {
89 int result;
90
91 __asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));
92 return (Uint16)result;
93 }
94 #elif defined(__GNUC__) && (defined(__m68k__) && !defined(__mcoldfire__))
95 static __inline__ Uint16 SDL_Swap16(Uint16 x)
96 {
97 __asm__("rorw #8,%0" : "=d" (x) : "0" (x) : "cc");
98 return x;
99 }
100 #else
101 static __inline__ Uint16 SDL_Swap16(Uint16 x) {
102 return SDL_static_cast(Uint16, ((x<<8)|(x>>8)));
103 }
104 #endif
105
106 #if defined(__GNUC__) && defined(__i386__) && \
107 !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
SDL_Swap32(Uint32 x)108 static __inline__ Uint32 SDL_Swap32(Uint32 x)
109 {
110 __asm__("bswap %0" : "=r" (x) : "0" (x));
111 return x;
112 }
113 #elif defined(__GNUC__) && defined(__x86_64__)
SDL_Swap32(Uint32 x)114 static __inline__ Uint32 SDL_Swap32(Uint32 x)
115 {
116 __asm__("bswapl %0" : "=r" (x) : "0" (x));
117 return x;
118 }
119 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
SDL_Swap32(Uint32 x)120 static __inline__ Uint32 SDL_Swap32(Uint32 x)
121 {
122 Uint32 result;
123
124 __asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));
125 __asm__("rlwimi %0,%2,8,8,15" : "=&r" (result) : "0" (result), "r" (x));
126 __asm__("rlwimi %0,%2,24,0,7" : "=&r" (result) : "0" (result), "r" (x));
127 return result;
128 }
129 #elif defined(__GNUC__) && (defined(__m68k__) && !defined(__mcoldfire__))
SDL_Swap32(Uint32 x)130 static __inline__ Uint32 SDL_Swap32(Uint32 x)
131 {
132 __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) : "0" (x) : "cc");
133 return x;
134 }
135 #else
SDL_Swap32(Uint32 x)136 static __inline__ Uint32 SDL_Swap32(Uint32 x) {
137 return SDL_static_cast(Uint32, ((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24)));
138 }
139 #endif
140
141 #ifdef SDL_HAS_64BIT_TYPE
142 #if defined(__GNUC__) && defined(__i386__) && \
143 !(__GNUC__ == 2 && __GNUC_MINOR__ <= 95 /* broken gcc version */)
SDL_Swap64(Uint64 x)144 static __inline__ Uint64 SDL_Swap64(Uint64 x)
145 {
146 union {
147 struct { Uint32 a,b; } s;
148 Uint64 u;
149 } v;
150 v.u = x;
151 __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
152 : "=r" (v.s.a), "=r" (v.s.b)
153 : "0" (v.s.a), "1" (v.s.b));
154 return v.u;
155 }
156 #elif defined(__GNUC__) && defined(__x86_64__)
SDL_Swap64(Uint64 x)157 static __inline__ Uint64 SDL_Swap64(Uint64 x)
158 {
159 __asm__("bswapq %0" : "=r" (x) : "0" (x));
160 return x;
161 }
162 #else
SDL_Swap64(Uint64 x)163 static __inline__ Uint64 SDL_Swap64(Uint64 x)
164 {
165 Uint32 hi, lo;
166
167 /* Separate into high and low 32-bit values and swap them */
168 lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
169 x >>= 32;
170 hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
171 x = SDL_Swap32(lo);
172 x <<= 32;
173 x |= SDL_Swap32(hi);
174 return (x);
175 }
176 #endif
177 #else
178 /* This is mainly to keep compilers from complaining in SDL code.
179 * If there is no real 64-bit datatype, then compilers will complain about
180 * the fake 64-bit datatype that SDL provides when it compiles user code.
181 */
182 #define SDL_Swap64(X) (X)
183 #endif /* SDL_HAS_64BIT_TYPE */
184 /*@}*/
185
186 /**
187 * @name SDL_SwapLE and SDL_SwapBE Functions
188 * Byteswap item from the specified endianness to the native endianness
189 */
190 /*@{*/
191 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
192 #define SDL_SwapLE16(X) (X)
193 #define SDL_SwapLE32(X) (X)
194 #define SDL_SwapLE64(X) (X)
195 #define SDL_SwapBE16(X) SDL_Swap16(X)
196 #define SDL_SwapBE32(X) SDL_Swap32(X)
197 #define SDL_SwapBE64(X) SDL_Swap64(X)
198 #else
199 #define SDL_SwapLE16(X) SDL_Swap16(X)
200 #define SDL_SwapLE32(X) SDL_Swap32(X)
201 #define SDL_SwapLE64(X) SDL_Swap64(X)
202 #define SDL_SwapBE16(X) (X)
203 #define SDL_SwapBE32(X) (X)
204 #define SDL_SwapBE64(X) (X)
205 #endif
206 /*@}*/
207
208 /* Ends C function definitions when using C++ */
209 #ifdef __cplusplus
210 }
211 #endif
212 #include "close_code.h"
213
214 #endif /* _SDL_endian_h */
215