1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2014 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
62extern "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 */)
70SDL_FORCE_INLINE Uint16
71SDL_Swap16(Uint16 x)
72{
73  __asm__("xchgb %b0,%h0": "=q"(x):"0"(x));
74    return x;
75}
76#elif defined(__GNUC__) && defined(__x86_64__)
77SDL_FORCE_INLINE Uint16
78SDL_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__))
84SDL_FORCE_INLINE Uint16
85SDL_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__)
93SDL_FORCE_INLINE Uint16
94SDL_Swap16(Uint16 x)
95{
96  __asm__("rorw #8,%0": "=d"(x): "0"(x):"cc");
97    return x;
98}
99#else
100SDL_FORCE_INLINE Uint16
101SDL_Swap16(Uint16 x)
102{
103    return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
104}
105#endif
106
107#if defined(__GNUC__) && defined(__i386__)
108SDL_FORCE_INLINE Uint32
109SDL_Swap32(Uint32 x)
110{
111  __asm__("bswap %0": "=r"(x):"0"(x));
112    return x;
113}
114#elif defined(__GNUC__) && defined(__x86_64__)
115SDL_FORCE_INLINE Uint32
116SDL_Swap32(Uint32 x)
117{
118  __asm__("bswapl %0": "=r"(x):"0"(x));
119    return x;
120}
121#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
122SDL_FORCE_INLINE Uint32
123SDL_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__)
133SDL_FORCE_INLINE Uint32
134SDL_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
140SDL_FORCE_INLINE Uint32
141SDL_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__)
149SDL_FORCE_INLINE Uint64
150SDL_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__)
167SDL_FORCE_INLINE Uint64
168SDL_Swap64(Uint64 x)
169{
170  __asm__("bswapq %0": "=r"(x):"0"(x));
171    return x;
172}
173#else
174SDL_FORCE_INLINE Uint64
175SDL_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
191SDL_FORCE_INLINE float
192SDL_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