1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20 */
21
22 /**
23 * \file SDL_endian.h
24 *
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 /**
34 * \name 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 * \file SDL_endian.h
67 */
68 #if defined(__GNUC__) && defined(__i386__) && \
69 !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
70 SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)71 SDL_Swap16(Uint16 x)
72 {
73 __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
74 return x;
75 }
76 #elif defined(__GNUC__) && defined(__x86_64__)
77 SDL_FORCE_INLINE Uint16
78 SDL_Swap16(Uint16 x)
79 {
80 __asm__("xchgb %b0,%h0": "=Q"(x):"0"(x));
81 return x;
82 }
83 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
84 SDL_FORCE_INLINE Uint16
85 SDL_Swap16(Uint16 x)
86 {
87 int result;
88
89 __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
90 return (Uint16)result;
91 }
92 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
93 SDL_FORCE_INLINE Uint16
94 SDL_Swap16(Uint16 x)
95 {
96 __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
97 return x;
98 }
99 #else
100 SDL_FORCE_INLINE Uint16
101 SDL_Swap16(Uint16 x)
102 {
103 return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
104 }
105 #endif
106
107 #if defined(__GNUC__) && defined(__i386__)
108 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)109 SDL_Swap32(Uint32 x)
110 {
111 __asm__("bswap %0": "=r"(x):"0"(x));
112 return x;
113 }
114 #elif defined(__GNUC__) && defined(__x86_64__)
115 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)116 SDL_Swap32(Uint32 x)
117 {
118 __asm__("bswapl %0": "=r"(x):"0"(x));
119 return x;
120 }
121 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
122 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)123 SDL_Swap32(Uint32 x)
124 {
125 Uint32 result;
126
127 __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
128 __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
129 __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
130 return result;
131 }
132 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
133 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)134 SDL_Swap32(Uint32 x)
135 {
136 __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
137 return x;
138 }
139 #else
140 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)141 SDL_Swap32(Uint32 x)
142 {
143 return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
144 ((x >> 8) & 0x0000FF00) | (x >> 24)));
145 }
146 #endif
147
148 #if defined(__GNUC__) && defined(__i386__)
149 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)150 SDL_Swap64(Uint64 x)
151 {
152 union
153 {
154 struct
155 {
156 Uint32 a, b;
157 } s;
158 Uint64 u;
159 } v;
160 v.u = x;
161 __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
162 "1"(v.s.
163 b));
164 return v.u;
165 }
166 #elif defined(__GNUC__) && defined(__x86_64__)
167 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)168 SDL_Swap64(Uint64 x)
169 {
170 __asm__("bswapq %0": "=r"(x):"0"(x));
171 return x;
172 }
173 #else
174 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)175 SDL_Swap64(Uint64 x)
176 {
177 Uint32 hi, lo;
178
179 /* Separate into high and low 32-bit values and swap them */
180 lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
181 x >>= 32;
182 hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
183 x = SDL_Swap32(lo);
184 x <<= 32;
185 x |= SDL_Swap32(hi);
186 return (x);
187 }
188 #endif
189
190
191 SDL_FORCE_INLINE float
SDL_SwapFloat(float x)192 SDL_SwapFloat(float x)
193 {
194 union
195 {
196 float f;
197 Uint32 ui32;
198 } swapper;
199 swapper.f = x;
200 swapper.ui32 = SDL_Swap32(swapper.ui32);
201 return swapper.f;
202 }
203
204
205 /**
206 * \name Swap to native
207 * Byteswap item from the specified endianness to the native endianness.
208 */
209 /* @{ */
210 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
211 #define SDL_SwapLE16(X) (X)
212 #define SDL_SwapLE32(X) (X)
213 #define SDL_SwapLE64(X) (X)
214 #define SDL_SwapFloatLE(X) (X)
215 #define SDL_SwapBE16(X) SDL_Swap16(X)
216 #define SDL_SwapBE32(X) SDL_Swap32(X)
217 #define SDL_SwapBE64(X) SDL_Swap64(X)
218 #define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
219 #else
220 #define SDL_SwapLE16(X) SDL_Swap16(X)
221 #define SDL_SwapLE32(X) SDL_Swap32(X)
222 #define SDL_SwapLE64(X) SDL_Swap64(X)
223 #define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
224 #define SDL_SwapBE16(X) (X)
225 #define SDL_SwapBE32(X) (X)
226 #define SDL_SwapBE64(X) (X)
227 #define SDL_SwapFloatBE(X) (X)
228 #endif
229 /* @} *//* Swap to native */
230
231 /* Ends C function definitions when using C++ */
232 #ifdef __cplusplus
233 }
234 #endif
235 #include "close_code.h"
236
237 #endif /* _SDL_endian_h */
238
239 /* vi: set ts=4 sw=4 expandtab: */
240