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handle src buffer underflow corner cases
[sdl_omap.git] / src / audio / SDL_mixer.c
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e14743d1 1/*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2009 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21*/
22#include "SDL_config.h"
23
24/* This provides the default mixing callback for the SDL audio routines */
25
26#include "SDL_cpuinfo.h"
27#include "SDL_timer.h"
28#include "SDL_audio.h"
29#include "SDL_sysaudio.h"
30#include "SDL_mixer_MMX.h"
31#include "SDL_mixer_MMX_VC.h"
32#include "SDL_mixer_m68k.h"
33
34/* This table is used to add two sound values together and pin
35 * the value to avoid overflow. (used with permission from ARDI)
36 * Changed to use 0xFE instead of 0xFF for better sound quality.
37 */
38static const Uint8 mix8[] =
39{
40 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
41 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
42 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
43 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
44 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
45 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
46 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
47 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
48 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
49 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
50 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
51 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
52 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
53 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
54 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
55 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
56 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
57 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
58 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
59 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
60 0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
61 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
62 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
63 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
64 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
65 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
66 0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
67 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
68 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
69 0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
70 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
71 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
72 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
73 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
74 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
75 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
76 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
77 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
78 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
79 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
80 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
81 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
82 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
83 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
84 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
85 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
86 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE
87};
88
89/* The volume ranges from 0 - 128 */
90#define ADJUST_VOLUME(s, v) (s = (s*v)/SDL_MIX_MAXVOLUME)
91#define ADJUST_VOLUME_U8(s, v) (s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)
92
93void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
94{
95 Uint16 format;
96
97 if ( volume == 0 ) {
98 return;
99 }
100 /* Mix the user-level audio format */
101 if ( current_audio ) {
102 if ( current_audio->convert.needed ) {
103 format = current_audio->convert.src_format;
104 } else {
105 format = current_audio->spec.format;
106 }
107 } else {
108 /* HACK HACK HACK */
109 format = AUDIO_S16;
110 }
111 switch (format) {
112
113 case AUDIO_U8: {
114#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
115 SDL_MixAudio_m68k_U8((char*)dst,(char*)src,(unsigned long)len,(long)volume,(char *)mix8);
116#else
117 Uint8 src_sample;
118
119 while ( len-- ) {
120 src_sample = *src;
121 ADJUST_VOLUME_U8(src_sample, volume);
122 *dst = mix8[*dst+src_sample];
123 ++dst;
124 ++src;
125 }
126#endif
127 }
128 break;
129
130 case AUDIO_S8: {
131#if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
132#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
133 if (SDL_HasMMX())
134 {
135 SDL_MixAudio_MMX_S8((char*)dst,(char*)src,(unsigned int)len,(int)volume);
136 }
137 else
138#elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
139 if (SDL_HasMMX())
140 {
141 SDL_MixAudio_MMX_S8_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
142 }
143 else
144#endif
145#endif
146
147#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
148 SDL_MixAudio_m68k_S8((char*)dst,(char*)src,(unsigned long)len,(long)volume);
149#else
150 {
151 Sint8 *dst8, *src8;
152 Sint8 src_sample;
153 int dst_sample;
154 const int max_audioval = ((1<<(8-1))-1);
155 const int min_audioval = -(1<<(8-1));
156
157 src8 = (Sint8 *)src;
158 dst8 = (Sint8 *)dst;
159 while ( len-- ) {
160 src_sample = *src8;
161 ADJUST_VOLUME(src_sample, volume);
162 dst_sample = *dst8 + src_sample;
163 if ( dst_sample > max_audioval ) {
164 *dst8 = max_audioval;
165 } else
166 if ( dst_sample < min_audioval ) {
167 *dst8 = min_audioval;
168 } else {
169 *dst8 = dst_sample;
170 }
171 ++dst8;
172 ++src8;
173 }
174 }
175#endif
176 }
177 break;
178
179 case AUDIO_S16LSB: {
180#if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
181#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
182 if (SDL_HasMMX())
183 {
184 SDL_MixAudio_MMX_S16((char*)dst,(char*)src,(unsigned int)len,(int)volume);
185 }
186 else
187#elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
188 if (SDL_HasMMX())
189 {
190 SDL_MixAudio_MMX_S16_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
191 }
192 else
193#endif
194#endif
195
196#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
197 SDL_MixAudio_m68k_S16LSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
198#else
199 {
200 Sint16 src1, src2;
201 int dst_sample;
202 const int max_audioval = ((1<<(16-1))-1);
203 const int min_audioval = -(1<<(16-1));
204
205 len /= 2;
206 while ( len-- ) {
207 src1 = ((src[1])<<8|src[0]);
208 ADJUST_VOLUME(src1, volume);
209 src2 = ((dst[1])<<8|dst[0]);
210 src += 2;
211 dst_sample = src1+src2;
212 if ( dst_sample > max_audioval ) {
213 dst_sample = max_audioval;
214 } else
215 if ( dst_sample < min_audioval ) {
216 dst_sample = min_audioval;
217 }
218 dst[0] = dst_sample&0xFF;
219 dst_sample >>= 8;
220 dst[1] = dst_sample&0xFF;
221 dst += 2;
222 }
223 }
224#endif
225 }
226 break;
227
228 case AUDIO_S16MSB: {
229#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
230 SDL_MixAudio_m68k_S16MSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
231#else
232 Sint16 src1, src2;
233 int dst_sample;
234 const int max_audioval = ((1<<(16-1))-1);
235 const int min_audioval = -(1<<(16-1));
236
237 len /= 2;
238 while ( len-- ) {
239 src1 = ((src[0])<<8|src[1]);
240 ADJUST_VOLUME(src1, volume);
241 src2 = ((dst[0])<<8|dst[1]);
242 src += 2;
243 dst_sample = src1+src2;
244 if ( dst_sample > max_audioval ) {
245 dst_sample = max_audioval;
246 } else
247 if ( dst_sample < min_audioval ) {
248 dst_sample = min_audioval;
249 }
250 dst[1] = dst_sample&0xFF;
251 dst_sample >>= 8;
252 dst[0] = dst_sample&0xFF;
253 dst += 2;
254 }
255#endif
256 }
257 break;
258
259 default: /* If this happens... FIXME! */
260 SDL_SetError("SDL_MixAudio(): unknown audio format");
261 return;
262 }
263}
264
SDL with some OMAP hardware support