1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2020 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 #elif defined(__OpenBSD__)
46 #include <endian.h>
47 #define SDL_BYTEORDER BYTE_ORDER
48 #else
49 #if defined(__hppa__) || \
50 defined(__m68k__) || defined(mc68000) || defined(_M_M68K) || \
51 (defined(__MIPS__) && defined(__MIPSEB__)) || \
52 defined(__ppc__) || defined(__POWERPC__) || defined(_M_PPC) || \
53 defined(__sparc__)
54 #define SDL_BYTEORDER SDL_BIG_ENDIAN
55 #else
56 #define SDL_BYTEORDER SDL_LIL_ENDIAN
57 #endif
58 #endif /* __linux__ */
59 #endif /* !SDL_BYTEORDER */
60
61
62 #include "begin_code.h"
63 /* Set up for C function definitions, even when using C++ */
64 #ifdef __cplusplus
65 extern "C" {
66 #endif
67
68 /**
69 * \file SDL_endian.h
70 */
71 #if defined(__GNUC__) && defined(__i386__) && \
72 !(__GNUC__ == 2 && __GNUC_MINOR__ == 95 /* broken gcc version */)
73 SDL_FORCE_INLINE Uint16
SDL_Swap16(Uint16 x)74 SDL_Swap16(Uint16 x)
75 {
76 __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
77 return x;
78 }
79 #elif defined(__GNUC__) && defined(__x86_64__)
80 SDL_FORCE_INLINE Uint16
81 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 SDL_FORCE_INLINE Uint16
88 SDL_Swap16(Uint16 x)
89 {
90 int result;
91
92 __asm__("rlwimi %0,%2,8,16,23": "=&r"(result):"0"(x >> 8), "r"(x));
93 return (Uint16)result;
94 }
95 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
96 SDL_FORCE_INLINE Uint16
97 SDL_Swap16(Uint16 x)
98 {
99 __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
100 return x;
101 }
102 #elif defined(__WATCOMC__) && defined(__386__)
103 extern _inline Uint16 SDL_Swap16(Uint16);
104 #pragma aux SDL_Swap16 = \
105 "xchg al, ah" \
106 parm [ax] \
107 modify [ax];
108 #else
109 SDL_FORCE_INLINE Uint16
110 SDL_Swap16(Uint16 x)
111 {
112 return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
113 }
114 #endif
115
116 #if defined(__GNUC__) && defined(__i386__)
117 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)118 SDL_Swap32(Uint32 x)
119 {
120 __asm__("bswap %0": "=r"(x):"0"(x));
121 return x;
122 }
123 #elif defined(__GNUC__) && defined(__x86_64__)
124 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)125 SDL_Swap32(Uint32 x)
126 {
127 __asm__("bswapl %0": "=r"(x):"0"(x));
128 return x;
129 }
130 #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
131 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)132 SDL_Swap32(Uint32 x)
133 {
134 Uint32 result;
135
136 __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
137 __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
138 __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
139 return result;
140 }
141 #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
142 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)143 SDL_Swap32(Uint32 x)
144 {
145 __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
146 return x;
147 }
148 #elif defined(__WATCOMC__) && defined(__386__)
149 extern _inline Uint32 SDL_Swap32(Uint32);
150 #ifndef __SW_3 /* 486+ */
151 #pragma aux SDL_Swap32 = \
152 "bswap eax" \
153 parm [eax] \
154 modify [eax];
155 #else /* 386-only */
156 #pragma aux SDL_Swap32 = \
157 "xchg al, ah" \
158 "ror eax, 16" \
159 "xchg al, ah" \
160 parm [eax] \
161 modify [eax];
162 #endif
163 #else
164 SDL_FORCE_INLINE Uint32
SDL_Swap32(Uint32 x)165 SDL_Swap32(Uint32 x)
166 {
167 return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
168 ((x >> 8) & 0x0000FF00) | (x >> 24)));
169 }
170 #endif
171
172 #if defined(__GNUC__) && defined(__i386__)
173 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)174 SDL_Swap64(Uint64 x)
175 {
176 union
177 {
178 struct
179 {
180 Uint32 a, b;
181 } s;
182 Uint64 u;
183 } v;
184 v.u = x;
185 __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
186 "1"(v.s.
187 b));
188 return v.u;
189 }
190 #elif defined(__GNUC__) && defined(__x86_64__)
191 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)192 SDL_Swap64(Uint64 x)
193 {
194 __asm__("bswapq %0": "=r"(x):"0"(x));
195 return x;
196 }
197 #else
198 SDL_FORCE_INLINE Uint64
SDL_Swap64(Uint64 x)199 SDL_Swap64(Uint64 x)
200 {
201 Uint32 hi, lo;
202
203 /* Separate into high and low 32-bit values and swap them */
204 lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
205 x >>= 32;
206 hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
207 x = SDL_Swap32(lo);
208 x <<= 32;
209 x |= SDL_Swap32(hi);
210 return (x);
211 }
212 #endif
213
214
215 SDL_FORCE_INLINE float
SDL_SwapFloat(float x)216 SDL_SwapFloat(float x)
217 {
218 union
219 {
220 float f;
221 Uint32 ui32;
222 } swapper;
223 swapper.f = x;
224 swapper.ui32 = SDL_Swap32(swapper.ui32);
225 return swapper.f;
226 }
227
228
229 /**
230 * \name Swap to native
231 * Byteswap item from the specified endianness to the native endianness.
232 */
233 /* @{ */
234 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
235 #define SDL_SwapLE16(X) (X)
236 #define SDL_SwapLE32(X) (X)
237 #define SDL_SwapLE64(X) (X)
238 #define SDL_SwapFloatLE(X) (X)
239 #define SDL_SwapBE16(X) SDL_Swap16(X)
240 #define SDL_SwapBE32(X) SDL_Swap32(X)
241 #define SDL_SwapBE64(X) SDL_Swap64(X)
242 #define SDL_SwapFloatBE(X) SDL_SwapFloat(X)
243 #else
244 #define SDL_SwapLE16(X) SDL_Swap16(X)
245 #define SDL_SwapLE32(X) SDL_Swap32(X)
246 #define SDL_SwapLE64(X) SDL_Swap64(X)
247 #define SDL_SwapFloatLE(X) SDL_SwapFloat(X)
248 #define SDL_SwapBE16(X) (X)
249 #define SDL_SwapBE32(X) (X)
250 #define SDL_SwapBE64(X) (X)
251 #define SDL_SwapFloatBE(X) (X)
252 #endif
253 /* @} *//* Swap to native */
254
255 /* Ends C function definitions when using C++ */
256 #ifdef __cplusplus
257 }
258 #endif
259 #include "close_code.h"
260
261 #endif /* SDL_endian_h_ */
262
263 /* vi: set ts=4 sw=4 expandtab: */
264