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1.1 root 1: /*
2: SDL - Simple DirectMedia Layer
3: Copyright (C) 1997-2004 Sam Lantinga
4:
5: This library is free software; you can redistribute it and/or
6: modify it under the terms of the GNU Library General Public
7: License as published by the Free Software Foundation; either
8: version 2 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: Library General Public License for more details.
14:
15: You should have received a copy of the GNU Library General Public
16: License along with this library; if not, write to the Free
17: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18:
19: Sam Lantinga
20: [email protected]
21: */
22:
23: #ifdef SAVE_RCSID
24: static char rcsid =
25: "@(#) $Id: SDL_endian.h,v 1.1.1.1 2005/11/18 23:23:29 rswindell Exp $";
26: #endif
27:
28: /* Functions for reading and writing endian-specific values */
29:
30: #ifndef _SDL_endian_h
31: #define _SDL_endian_h
32:
33: /* These functions read and write data of the specified endianness,
34: dynamically translating to the host machine endianness.
35:
36: e.g.: If you want to read a 16 bit value on big-endian machine from
37: an open file containing little endian values, you would use:
38: value = SDL_ReadLE16(rp);
39: Note that the read/write functions use SDL_RWops pointers
40: instead of FILE pointers. This allows you to read and write
41: endian values from large chunks of memory as well as files
42: and other data sources.
43: */
44:
45: #include <stdio.h>
46:
47: #include "SDL_types.h"
48: #include "SDL_rwops.h"
49: #include "SDL_byteorder.h"
50:
51: #include "begin_code.h"
52: /* Set up for C function definitions, even when using C++ */
53: #ifdef __cplusplus
54: extern "C" {
55: #endif
56:
57: /* Use inline functions for compilers that support them, and static
58: functions for those that do not. Because these functions become
59: static for compilers that do not support inline functions, this
60: header should only be included in files that actually use them.
61: */
62: #if defined(__GNUC__) && defined(__i386__)
63: static __inline__ Uint16 SDL_Swap16(Uint16 x)
64: {
65: __asm__("xchgb %b0,%h0" : "=q" (x) : "0" (x));
66: return x;
67: }
68: #elif defined(__GNUC__) && defined(__x86_64__)
69: static __inline__ Uint16 SDL_Swap16(Uint16 x)
70: {
71: __asm__("xchgb %b0,%h0" : "=Q" (x) : "0" (x));
72: return x;
73: }
74: #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
75: static __inline__ Uint16 SDL_Swap16(Uint16 x)
76: {
77: Uint16 result;
78:
79: __asm__("rlwimi %0,%2,8,16,23" : "=&r" (result) : "0" (x >> 8), "r" (x));
80: return result;
81: }
82: #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
83: static __inline__ Uint16 SDL_Swap16(Uint16 x)
84: {
85: __asm__("rorw #8,%0" : "=d" (x) : "0" (x) : "cc");
86: return x;
87: }
88: #else
89: static __inline__ Uint16 SDL_Swap16(Uint16 x) {
90: return((x<<8)|(x>>8));
91: }
92: #endif
93:
94: #if defined(__GNUC__) && defined(__i386__)
95: static __inline__ Uint32 SDL_Swap32(Uint32 x)
96: {
97: __asm__("bswap %0" : "=r" (x) : "0" (x));
98: return x;
99: }
100: #elif defined(__GNUC__) && defined(__x86_64__)
101: static __inline__ Uint32 SDL_Swap32(Uint32 x)
102: {
103: __asm__("bswapl %0" : "=r" (x) : "0" (x));
104: return x;
105: }
106: #elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
107: static __inline__ Uint32 SDL_Swap32(Uint32 x)
108: {
109: Uint32 result;
110:
111: __asm__("rlwimi %0,%2,24,16,23" : "=&r" (result) : "0" (x>>24), "r" (x));
112: __asm__("rlwimi %0,%2,8,8,15" : "=&r" (result) : "0" (result), "r" (x));
113: __asm__("rlwimi %0,%2,24,0,7" : "=&r" (result) : "0" (result), "r" (x));
114: return result;
115: }
116: #elif defined(__GNUC__) && (defined(__M68000__) || defined(__M68020__))
117: static __inline__ Uint32 SDL_Swap32(Uint32 x)
118: {
119: __asm__("rorw #8,%0\n\tswap %0\n\trorw #8,%0" : "=d" (x) : "0" (x) : "cc");
120: return x;
121: }
122: #else
123: static __inline__ Uint32 SDL_Swap32(Uint32 x) {
124: return((x<<24)|((x<<8)&0x00FF0000)|((x>>8)&0x0000FF00)|(x>>24));
125: }
126: #endif
127:
128: #ifdef SDL_HAS_64BIT_TYPE
129: #if defined(__GNUC__) && defined(__i386__)
130: static __inline__ Uint64 SDL_Swap64(Uint64 x)
131: {
132: union {
133: struct { Uint32 a,b; } s;
134: Uint64 u;
135: } v;
136: v.u = x;
137: __asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
138: : "=r" (v.s.a), "=r" (v.s.b)
139: : "0" (v.s.a), "1" (v.s.b));
140: return v.u;
141: }
142: #elif defined(__GNUC__) && defined(__x86_64__)
143: static __inline__ Uint64 SDL_Swap64(Uint64 x)
144: {
145: __asm__("bswapq %0" : "=r" (x) : "0" (x));
146: return x;
147: }
148: #else
149: static __inline__ Uint64 SDL_Swap64(Uint64 x)
150: {
151: Uint32 hi, lo;
152:
153: /* Separate into high and low 32-bit values and swap them */
154: lo = (Uint32)(x&0xFFFFFFFF);
155: x >>= 32;
156: hi = (Uint32)(x&0xFFFFFFFF);
157: x = SDL_Swap32(lo);
158: x <<= 32;
159: x |= SDL_Swap32(hi);
160: return(x);
161: }
162: #endif
163: #else
164: /* This is mainly to keep compilers from complaining in SDL code.
165: If there is no real 64-bit datatype, then compilers will complain about
166: the fake 64-bit datatype that SDL provides when it compiles user code.
167: */
168: #define SDL_Swap64(X) (X)
169: #endif /* SDL_HAS_64BIT_TYPE */
170:
171:
172: /* Byteswap item from the specified endianness to the native endianness */
173: #if SDL_BYTEORDER == SDL_LIL_ENDIAN
174: #define SDL_SwapLE16(X) (X)
175: #define SDL_SwapLE32(X) (X)
176: #define SDL_SwapLE64(X) (X)
177: #define SDL_SwapBE16(X) SDL_Swap16(X)
178: #define SDL_SwapBE32(X) SDL_Swap32(X)
179: #define SDL_SwapBE64(X) SDL_Swap64(X)
180: #else
181: #define SDL_SwapLE16(X) SDL_Swap16(X)
182: #define SDL_SwapLE32(X) SDL_Swap32(X)
183: #define SDL_SwapLE64(X) SDL_Swap64(X)
184: #define SDL_SwapBE16(X) (X)
185: #define SDL_SwapBE32(X) (X)
186: #define SDL_SwapBE64(X) (X)
187: #endif
188:
189: /* Read an item of the specified endianness and return in native format */
190: extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
191: extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
192: extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
193: extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
194: extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
195: extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
196:
197: /* Write an item of native format to the specified endianness */
198: extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
199: extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
200: extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
201: extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
202: extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
203: extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
204:
205:
206: /* Ends C function definitions when using C++ */
207: #ifdef __cplusplus
208: }
209: #endif
210: #include "close_code.h"
211:
212: #endif /* _SDL_endian_h */
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