diff options
Diffstat (limited to 'apps/codecs/libgme/hes_apu_adpcm.c')
-rw-r--r-- | apps/codecs/libgme/hes_apu_adpcm.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/apps/codecs/libgme/hes_apu_adpcm.c b/apps/codecs/libgme/hes_apu_adpcm.c new file mode 100644 index 0000000000..b2f78ff71f --- /dev/null +++ b/apps/codecs/libgme/hes_apu_adpcm.c | |||
@@ -0,0 +1,297 @@ | |||
1 | // Game_Music_Emu 0.6-pre. http://www.slack.net/~ant/ | ||
2 | |||
3 | #include "hes_apu_adpcm.h" | ||
4 | |||
5 | /* Copyright (C) 2006-2008 Shay Green. This module is free software; you | ||
6 | can redistribute it and/or modify it under the terms of the GNU Lesser | ||
7 | General Public License as published by the Free Software Foundation; either | ||
8 | version 2.1 of the License, or (at your option) any later version. This | ||
9 | module is distributed in the hope that it will be useful, but WITHOUT ANY | ||
10 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | ||
11 | FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more | ||
12 | details. You should have received a copy of the GNU Lesser General Public | ||
13 | License along with this module; if not, write to the Free Software Foundation, | ||
14 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ | ||
15 | |||
16 | |||
17 | void Adpcm_init( struct Hes_Apu_Adpcm* this ) | ||
18 | { | ||
19 | this->output = NULL; | ||
20 | memset( &this->state, 0, sizeof( this->state ) ); | ||
21 | Adpcm_reset( this ); | ||
22 | } | ||
23 | |||
24 | void Adpcm_reset( struct Hes_Apu_Adpcm* this ) | ||
25 | { | ||
26 | this->last_time = 0; | ||
27 | this->next_timer = 0; | ||
28 | this->last_amp = 0; | ||
29 | |||
30 | memset( &this->state.pcmbuf, 0, sizeof(this->state.pcmbuf) ); | ||
31 | memset( &this->state.port, 0, sizeof(this->state.port) ); | ||
32 | |||
33 | this->state.ad_sample = 0; | ||
34 | this->state.ad_ref_index = 0; | ||
35 | |||
36 | this->state.addr = 0; | ||
37 | this->state.freq = 0; | ||
38 | this->state.writeptr = 0; | ||
39 | this->state.readptr = 0; | ||
40 | this->state.playflag = 0; | ||
41 | this->state.repeatflag = 0; | ||
42 | this->state.length = 0; | ||
43 | this->state.volume = 0xFF; | ||
44 | this->state.fadetimer = 0; | ||
45 | this->state.fadecount = 0; | ||
46 | } | ||
47 | |||
48 | static short stepsize[49] = { | ||
49 | 16, 17, 19, 21, 23, 25, 28, | ||
50 | 31, 34, 37, 41, 45, 50, 55, | ||
51 | 60, 66, 73, 80, 88, 97, 107, | ||
52 | 118, 130, 143, 157, 173, 190, 209, | ||
53 | 230, 253, 279, 307, 337, 371, 408, | ||
54 | 449, 494, 544, 598, 658, 724, 796, | ||
55 | 876, 963,1060,1166,1282,1411,1552 | ||
56 | }; | ||
57 | |||
58 | static int Adpcm_decode( struct Hes_Apu_Adpcm* this,int code ) ICODE_ATTR; | ||
59 | static int Adpcm_decode( struct Hes_Apu_Adpcm* this,int code ) | ||
60 | { | ||
61 | struct State* state = &this->state; | ||
62 | int step = stepsize[state->ad_ref_index]; | ||
63 | int delta; | ||
64 | int c = code & 7; | ||
65 | #if 1 | ||
66 | delta = 0; | ||
67 | if ( c & 4 ) delta += step; | ||
68 | step >>= 1; | ||
69 | if ( c & 2 ) delta += step; | ||
70 | step >>= 1; | ||
71 | if ( c & 1 ) delta += step; | ||
72 | step >>= 1; | ||
73 | delta += step; | ||
74 | #else | ||
75 | delta = ( ( c + c + 1 ) * step ) / 8; // maybe faster, but introduces rounding | ||
76 | #endif | ||
77 | if ( c != code ) | ||
78 | { | ||
79 | state->ad_sample -= delta; | ||
80 | if ( state->ad_sample < -2048 ) | ||
81 | state->ad_sample = -2048; | ||
82 | } | ||
83 | else | ||
84 | { | ||
85 | state->ad_sample += delta; | ||
86 | if ( state->ad_sample > 2047 ) | ||
87 | state->ad_sample = 2047; | ||
88 | } | ||
89 | |||
90 | static int const steps [8] ICONST_ATTR = { | ||
91 | -1, -1, -1, -1, 2, 4, 6, 8 | ||
92 | }; | ||
93 | state->ad_ref_index += steps [c]; | ||
94 | if ( state->ad_ref_index < 0 ) | ||
95 | state->ad_ref_index = 0; | ||
96 | else if ( state->ad_ref_index > 48 ) | ||
97 | state->ad_ref_index = 48; | ||
98 | |||
99 | return state->ad_sample; | ||
100 | } | ||
101 | |||
102 | static void Adpcm_run_until( struct Hes_Apu_Adpcm* this, blip_time_t end_time ) ICODE_ATTR; | ||
103 | static void Adpcm_run_until( struct Hes_Apu_Adpcm* this, blip_time_t end_time ) | ||
104 | { | ||
105 | struct State* state = &this->state; | ||
106 | int volume = state->volume; | ||
107 | int fadetimer = state->fadetimer; | ||
108 | int fadecount = state->fadecount; | ||
109 | int last_time = this->last_time; | ||
110 | double next_timer = this->next_timer; | ||
111 | int last_amp = this->last_amp; | ||
112 | |||
113 | struct Blip_Buffer* output = this->output; // cache often-used values | ||
114 | |||
115 | while ( state->playflag && last_time < end_time ) | ||
116 | { | ||
117 | while ( last_time >= next_timer ) | ||
118 | { | ||
119 | if ( fadetimer ) | ||
120 | { | ||
121 | if ( fadecount > 0 ) | ||
122 | { | ||
123 | fadecount--; | ||
124 | volume = 0xFF * fadecount / fadetimer; | ||
125 | } | ||
126 | else if ( fadecount < 0 ) | ||
127 | { | ||
128 | fadecount++; | ||
129 | volume = 0xFF - ( 0xFF * fadecount / fadetimer ); | ||
130 | } | ||
131 | } | ||
132 | next_timer += 7159.091; | ||
133 | } | ||
134 | int amp; | ||
135 | if ( state->ad_low_nibble ) | ||
136 | { | ||
137 | amp = Adpcm_decode( this, state->pcmbuf[ state->playptr ] & 0x0F ); | ||
138 | state->ad_low_nibble = false; | ||
139 | state->playptr++; | ||
140 | state->playedsamplecount++; | ||
141 | if ( state->playedsamplecount == state->playlength ) | ||
142 | { | ||
143 | state->playflag = 0; | ||
144 | } | ||
145 | } | ||
146 | else | ||
147 | { | ||
148 | amp = Adpcm_decode( this, state->pcmbuf[ state->playptr ] >> 4 ); | ||
149 | state->ad_low_nibble = true; | ||
150 | } | ||
151 | amp = amp * volume / 0xFF; | ||
152 | int delta = amp - last_amp; | ||
153 | if ( output && delta ) | ||
154 | { | ||
155 | last_amp = amp; | ||
156 | Synth_offset_inline( &this->synth, last_time, delta, output ); | ||
157 | } | ||
158 | last_time += state->freq; | ||
159 | } | ||
160 | |||
161 | if ( !state->playflag ) | ||
162 | { | ||
163 | while ( next_timer <= end_time ) next_timer += 7159.091; | ||
164 | last_time = end_time; | ||
165 | } | ||
166 | |||
167 | this->last_time = last_time; | ||
168 | this->next_timer = next_timer; | ||
169 | this->last_amp = last_amp; | ||
170 | state->volume = volume; | ||
171 | state->fadetimer = fadetimer; | ||
172 | state->fadecount = fadecount; | ||
173 | } | ||
174 | |||
175 | void Adpcm_write_data( struct Hes_Apu_Adpcm* this, blip_time_t time, int addr, int data ) | ||
176 | { | ||
177 | if ( time > this->last_time ) Adpcm_run_until( this, time ); | ||
178 | struct State* state = &this->state; | ||
179 | |||
180 | data &= 0xFF; | ||
181 | state->port[ addr & 15 ] = data; | ||
182 | switch ( addr & 15 ) | ||
183 | { | ||
184 | case 8: | ||
185 | state->addr &= 0xFF00; | ||
186 | state->addr |= data; | ||
187 | break; | ||
188 | case 9: | ||
189 | state->addr &= 0xFF; | ||
190 | state->addr |= data << 8; | ||
191 | break; | ||
192 | case 10: | ||
193 | state->pcmbuf[ state->writeptr++ ] = data; | ||
194 | state->playlength ++; | ||
195 | break; | ||
196 | case 11: | ||
197 | dprintf("ADPCM DMA 0x%02X", data); | ||
198 | break; | ||
199 | case 13: | ||
200 | if ( data & 0x80 ) | ||
201 | { | ||
202 | state->addr = 0; | ||
203 | state->freq = 0; | ||
204 | state->writeptr = 0; | ||
205 | state->readptr = 0; | ||
206 | state->playflag = 0; | ||
207 | state->repeatflag = 0; | ||
208 | state->length = 0; | ||
209 | state->volume = 0xFF; | ||
210 | } | ||
211 | if ( ( data & 3 ) == 3 ) | ||
212 | { | ||
213 | state->writeptr = state->addr; | ||
214 | } | ||
215 | if ( data & 8 ) | ||
216 | { | ||
217 | state->readptr = state->addr ? state->addr - 1 : state->addr; | ||
218 | } | ||
219 | if ( data & 0x10 ) | ||
220 | { | ||
221 | state->length = state->addr; | ||
222 | } | ||
223 | state->repeatflag = data & 0x20; | ||
224 | state->playflag = data & 0x40; | ||
225 | if ( state->playflag ) | ||
226 | { | ||
227 | state->playptr = state->readptr; | ||
228 | state->playlength = state->length + 1; | ||
229 | state->playedsamplecount = 0; | ||
230 | state->ad_sample = 0; | ||
231 | state->ad_low_nibble = false; | ||
232 | } | ||
233 | break; | ||
234 | case 14: | ||
235 | state->freq = 7159091 / ( 32000 / ( 16 - ( data & 15 ) ) ); | ||
236 | break; | ||
237 | case 15: | ||
238 | switch ( data & 15 ) | ||
239 | { | ||
240 | case 0: | ||
241 | case 8: | ||
242 | case 12: | ||
243 | state->fadetimer = -100; | ||
244 | state->fadecount = state->fadetimer; | ||
245 | break; | ||
246 | case 10: | ||
247 | state->fadetimer = 5000; | ||
248 | state->fadecount = state->fadetimer; | ||
249 | break; | ||
250 | case 14: | ||
251 | state->fadetimer = 1500; | ||
252 | state->fadecount = state->fadetimer; | ||
253 | break; | ||
254 | } | ||
255 | break; | ||
256 | } | ||
257 | } | ||
258 | |||
259 | int Adpcm_read_data( struct Hes_Apu_Adpcm* this, blip_time_t time, int addr ) | ||
260 | { | ||
261 | if ( time > this->last_time ) Adpcm_run_until( this, time ); | ||
262 | |||
263 | struct State* state = &this->state; | ||
264 | switch ( addr & 15 ) | ||
265 | { | ||
266 | case 10: | ||
267 | return state->pcmbuf [state->readptr++]; | ||
268 | case 11: | ||
269 | return state->port [11] & ~1; | ||
270 | case 12: | ||
271 | if (!state->playflag) | ||
272 | { | ||
273 | state->port [12] |= 1; | ||
274 | state->port [12] &= ~8; | ||
275 | } | ||
276 | else | ||
277 | { | ||
278 | state->port [12] &= ~1; | ||
279 | state->port [12] |= 8; | ||
280 | } | ||
281 | return state->port [12]; | ||
282 | case 13: | ||
283 | return state->port [13]; | ||
284 | } | ||
285 | |||
286 | return 0xFF; | ||
287 | } | ||
288 | |||
289 | void Adpcm_end_frame( struct Hes_Apu_Adpcm* this, blip_time_t end_time ) | ||
290 | { | ||
291 | Adpcm_run_until( this, end_time ); | ||
292 | this->last_time -= end_time; | ||
293 | this->next_timer -= (double)end_time; | ||
294 | check( last_time >= 0 ); | ||
295 | if ( this->output ) | ||
296 | Blip_set_modified( this->output ); | ||
297 | } | ||