Atlas - SDL_endian.h
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <[email protected]>
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#elif defined(__WATCOMC__) && defined(__386__)
100extern _inline Uint16 SDL_Swap16(Uint16);
101#pragma aux SDL_Swap16 = \
102  "xchg al, ah" \
103  parm   [ax]   \
104  modify [ax];
105#else
106SDL_FORCE_INLINE Uint16
107SDL_Swap16(Uint16 x)
108{
109    return SDL_static_cast(Uint16, ((x << 8) | (x >> 8)));
110}
111#endif
112
113#if defined(__GNUC__) && defined(__i386__)
114SDL_FORCE_INLINE Uint32
115SDL_Swap32(Uint32 x)
116{
117  __asm__("bswap %0": "=r"(x):"0"(x));
118    return x;
119}
120#elif defined(__GNUC__) && defined(__x86_64__)
121SDL_FORCE_INLINE Uint32
122SDL_Swap32(Uint32 x)
123{
124  __asm__("bswapl %0": "=r"(x):"0"(x));
125    return x;
126}
127#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
128SDL_FORCE_INLINE Uint32
129SDL_Swap32(Uint32 x)
130{
131    Uint32 result;
132
133  __asm__("rlwimi %0,%2,24,16,23": "=&r"(result):"0"(x >> 24), "r"(x));
134  __asm__("rlwimi %0,%2,8,8,15": "=&r"(result):"0"(result), "r"(x));
135  __asm__("rlwimi %0,%2,24,0,7": "=&r"(result):"0"(result), "r"(x));
136    return result;
137}
138#elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__)) && !defined(__mcoldfire__)
139SDL_FORCE_INLINE Uint32
140SDL_Swap32(Uint32 x)
141{
142  __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0": "=d"(x): "0"(x):"cc");
143    return x;
144}
145#elif defined(__WATCOMC__) && defined(__386__)
146extern _inline Uint32 SDL_Swap32(Uint32);
147#ifndef __SW_3 /* 486+ */
148#pragma aux SDL_Swap32 = \
149  "bswap eax"  \
150  parm   [eax] \
151  modify [eax];
152#else  /* 386-only */
153#pragma aux SDL_Swap32 = \
154  "xchg al, ah"  \
155  "ror  eax, 16" \
156  "xchg al, ah"  \
157  parm   [eax]   \
158  modify [eax];
159#endif
160#else
161SDL_FORCE_INLINE Uint32
162SDL_Swap32(Uint32 x)
163{
164    return SDL_static_cast(Uint32, ((x << 24) | ((x << 8) & 0x00FF0000) |
165                                    ((x >> 8) & 0x0000FF00) | (x >> 24)));
166}
167#endif
168
169#if defined(__GNUC__) && defined(__i386__)
170SDL_FORCE_INLINE Uint64
171SDL_Swap64(Uint64 x)
172{
173    union
174    {
175        struct
176        {
177            Uint32 a, b;
178        } s;
179        Uint64 u;
180    } v;
181    v.u = x;
182  __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1": "=r"(v.s.a), "=r"(v.s.b):"0"(v.s.a),
183            "1"(v.s.
184                b));
185    return v.u;
186}
187#elif defined(__GNUC__) && defined(__x86_64__)
188SDL_FORCE_INLINE Uint64
189SDL_Swap64(Uint64 x)
190{
191  __asm__("bswapq %0": "=r"(x):"0"(x));
192    return x;
193}
194#else
195SDL_FORCE_INLINE Uint64
196SDL_Swap64(Uint64 x)
197{
198    Uint32 hi, lo;
199
200    /* Separate into high and low 32-bit values and swap them */
201    lo = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
202    x >>= 32;
203    hi = SDL_static_cast(Uint32, x & 0xFFFFFFFF);
204    x = SDL_Swap32(lo);
205    x <<= 32;
206    x |= SDL_Swap32(hi);
207    return (x);
208}
209#endif
210
211
212SDL_FORCE_INLINE float
213SDL_SwapFloat(float x)
214{
215    union
216    {
217        float f;
218        Uint32 ui32;
219    } swapper;
220    swapper.f = x;
221    swapper.ui32 = SDL_Swap32(swapper.ui32);
222    return swapper.f;
223}
224
225
226/**
227 *  \name Swap to native
228 *  Byteswap item from the specified endianness to the native endianness.
229 */
230/* @{ */
231#if SDL_BYTEORDER == SDL_LIL_ENDIAN
232#define SDL_SwapLE16(X) (X)
233#define SDL_SwapLE32(X) (X)
234#define SDL_SwapLE64(X) (X)
235#define SDL_SwapFloatLE(X)  (X)
236#define SDL_SwapBE16(X) SDL_Swap16(X)
237#define SDL_SwapBE32(X) SDL_Swap32(X)
238#define SDL_SwapBE64(X) SDL_Swap64(X)
239#define SDL_SwapFloatBE(X)  SDL_SwapFloat(X)
240#else
241#define SDL_SwapLE16(X) SDL_Swap16(X)
242#define SDL_SwapLE32(X) SDL_Swap32(X)
243#define SDL_SwapLE64(X) SDL_Swap64(X)
244#define SDL_SwapFloatLE(X)  SDL_SwapFloat(X)
245#define SDL_SwapBE16(X) (X)
246#define SDL_SwapBE32(X) (X)
247#define SDL_SwapBE64(X) (X)
248#define SDL_SwapFloatBE(X)  (X)
249#endif
250/* @} *//* Swap to native */
251
252/* Ends C function definitions when using C++ */
253#ifdef __cplusplus
254}
255#endif
256#include "close_code.h"
257
258#endif /* SDL_endian_h_ */
259
260/* vi: set ts=4 sw=4 expandtab: */
261
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