Commit | Line | Data |
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ef79bbde P |
1 | /***************************************************************************\r |
2 | reverb.c - description\r | |
3 | -------------------\r | |
4 | begin : Wed May 15 2002\r | |
5 | copyright : (C) 2002 by Pete Bernert\r | |
6 | email : BlackDove@addcom.de\r | |
1775933a | 7 | \r |
8 | Portions (C) GraÅžvydas "notaz" Ignotas, 2010-2011\r | |
9 | Portions (C) SPU2-X, gigaherz, Pcsx2 Development Team\r | |
10 | \r | |
ef79bbde P |
11 | ***************************************************************************/\r |
12 | /***************************************************************************\r | |
13 | * *\r | |
14 | * This program is free software; you can redistribute it and/or modify *\r | |
15 | * it under the terms of the GNU General Public License as published by *\r | |
16 | * the Free Software Foundation; either version 2 of the License, or *\r | |
17 | * (at your option) any later version. See also the license.txt file for *\r | |
18 | * additional informations. *\r | |
19 | * *\r | |
20 | ***************************************************************************/\r | |
21 | \r | |
22 | #include "stdafx.h"\r | |
23 | \r | |
24 | #define _IN_REVERB\r | |
25 | \r | |
26 | // will be included from spu.c\r | |
27 | #ifdef _IN_SPU\r | |
28 | \r | |
ef79bbde P |
29 | ////////////////////////////////////////////////////////////////////////\r |
30 | // START REVERB\r | |
31 | ////////////////////////////////////////////////////////////////////////\r | |
32 | \r | |
33 | INLINE void StartREVERB(int ch)\r | |
34 | {\r | |
3154bfab | 35 | if(s_chan[ch].bReverb && (spu.spuCtrl&0x80)) // reverb possible?\r |
ef79bbde | 36 | {\r |
3154bfab | 37 | s_chan[ch].bRVBActive=!!spu_config.iUseReverb;\r |
ef79bbde P |
38 | }\r |
39 | else s_chan[ch].bRVBActive=0; // else -> no reverb\r | |
40 | }\r | |
41 | \r | |
42 | ////////////////////////////////////////////////////////////////////////\r | |
43 | // HELPER FOR NEILL'S REVERB: re-inits our reverb mixing buf\r | |
44 | ////////////////////////////////////////////////////////////////////////\r | |
45 | \r | |
650adfd2 | 46 | INLINE void InitREVERB(int ns_to)\r |
ef79bbde | 47 | {\r |
3154bfab | 48 | memset(spu.sRVBStart,0,ns_to*sizeof(spu.sRVBStart[0])*2);\r |
ef79bbde P |
49 | }\r |
50 | \r | |
51 | ////////////////////////////////////////////////////////////////////////\r | |
52 | \r | |
1775933a | 53 | INLINE int rvb2ram_offs(int curr, int space, int iOff)\r |
ef79bbde | 54 | {\r |
1775933a | 55 | iOff += curr;\r |
56 | if (iOff >= 0x40000) iOff -= space;\r | |
57 | return iOff;\r | |
ef79bbde P |
58 | }\r |
59 | \r | |
1775933a | 60 | // get_buffer content helper: takes care about wraps\r |
61 | #define g_buffer(var) \\r | |
3154bfab | 62 | ((int)(signed short)spu.spuMem[rvb2ram_offs(curr_addr, space, rvb.n##var)])\r |
ef79bbde | 63 | \r |
1775933a | 64 | // saturate iVal and store it as var\r |
65 | #define s_buffer(var, iVal) \\r | |
66 | ssat32_to_16(iVal); \\r | |
3154bfab | 67 | spu.spuMem[rvb2ram_offs(curr_addr, space, rvb.n##var)] = iVal\r |
ef79bbde | 68 | \r |
1775933a | 69 | #define s_buffer1(var, iVal) \\r |
70 | ssat32_to_16(iVal); \\r | |
3154bfab | 71 | spu.spuMem[rvb2ram_offs(curr_addr, space, rvb.n##var + 1)] = iVal\r |
ef79bbde P |
72 | \r |
73 | ////////////////////////////////////////////////////////////////////////\r | |
74 | \r | |
1775933a | 75 | // portions based on spu2-x from PCSX2\r |
650adfd2 | 76 | static void MixREVERB(int ns_to)\r |
ef79bbde | 77 | {\r |
1775933a | 78 | int l_old = rvb.iRVBLeft;\r |
79 | int r_old = rvb.iRVBRight;\r | |
80 | int curr_addr = rvb.CurrAddr;\r | |
81 | int space = 0x40000 - rvb.StartAddr;\r | |
650adfd2 | 82 | int l = 0, r = 0, ns;\r |
1775933a | 83 | \r |
650adfd2 | 84 | for (ns = 0; ns < ns_to * 2; )\r |
ef79bbde | 85 | {\r |
1775933a | 86 | int IIR_ALPHA = rvb.IIR_ALPHA;\r |
87 | int ACC0, ACC1, FB_A0, FB_A1, FB_B0, FB_B1;\r | |
88 | int mix_dest_a0, mix_dest_a1, mix_dest_b0, mix_dest_b1;\r | |
89 | \r | |
3154bfab | 90 | int input_L = spu.sRVBStart[ns] * rvb.IN_COEF_L;\r |
91 | int input_R = spu.sRVBStart[ns+1] * rvb.IN_COEF_R;\r | |
1775933a | 92 | \r |
93 | int IIR_INPUT_A0 = ((g_buffer(IIR_SRC_A0) * rvb.IIR_COEF) + input_L) >> 15;\r | |
94 | int IIR_INPUT_A1 = ((g_buffer(IIR_SRC_A1) * rvb.IIR_COEF) + input_R) >> 15;\r | |
95 | int IIR_INPUT_B0 = ((g_buffer(IIR_SRC_B0) * rvb.IIR_COEF) + input_L) >> 15;\r | |
96 | int IIR_INPUT_B1 = ((g_buffer(IIR_SRC_B1) * rvb.IIR_COEF) + input_R) >> 15;\r | |
97 | \r | |
98 | int iir_dest_a0 = g_buffer(IIR_DEST_A0);\r | |
99 | int iir_dest_a1 = g_buffer(IIR_DEST_A1);\r | |
100 | int iir_dest_b0 = g_buffer(IIR_DEST_B0);\r | |
101 | int iir_dest_b1 = g_buffer(IIR_DEST_B1);\r | |
102 | \r | |
103 | int IIR_A0 = iir_dest_a0 + ((IIR_INPUT_A0 - iir_dest_a0) * IIR_ALPHA >> 15);\r | |
104 | int IIR_A1 = iir_dest_a1 + ((IIR_INPUT_A1 - iir_dest_a1) * IIR_ALPHA >> 15);\r | |
105 | int IIR_B0 = iir_dest_b0 + ((IIR_INPUT_B0 - iir_dest_b0) * IIR_ALPHA >> 15);\r | |
106 | int IIR_B1 = iir_dest_b1 + ((IIR_INPUT_B1 - iir_dest_b1) * IIR_ALPHA >> 15);\r | |
107 | \r | |
108 | s_buffer1(IIR_DEST_A0, IIR_A0);\r | |
109 | s_buffer1(IIR_DEST_A1, IIR_A1);\r | |
110 | s_buffer1(IIR_DEST_B0, IIR_B0);\r | |
111 | s_buffer1(IIR_DEST_B1, IIR_B1);\r | |
112 | \r | |
113 | ACC0 = (g_buffer(ACC_SRC_A0) * rvb.ACC_COEF_A +\r | |
114 | g_buffer(ACC_SRC_B0) * rvb.ACC_COEF_B +\r | |
115 | g_buffer(ACC_SRC_C0) * rvb.ACC_COEF_C +\r | |
116 | g_buffer(ACC_SRC_D0) * rvb.ACC_COEF_D) >> 15;\r | |
117 | ACC1 = (g_buffer(ACC_SRC_A1) * rvb.ACC_COEF_A +\r | |
118 | g_buffer(ACC_SRC_B1) * rvb.ACC_COEF_B +\r | |
119 | g_buffer(ACC_SRC_C1) * rvb.ACC_COEF_C +\r | |
120 | g_buffer(ACC_SRC_D1) * rvb.ACC_COEF_D) >> 15;\r | |
121 | \r | |
122 | FB_A0 = g_buffer(FB_SRC_A0);\r | |
123 | FB_A1 = g_buffer(FB_SRC_A1);\r | |
124 | FB_B0 = g_buffer(FB_SRC_B0);\r | |
125 | FB_B1 = g_buffer(FB_SRC_B1);\r | |
126 | \r | |
127 | mix_dest_a0 = ACC0 - ((FB_A0 * rvb.FB_ALPHA) >> 15);\r | |
128 | mix_dest_a1 = ACC1 - ((FB_A1 * rvb.FB_ALPHA) >> 15);\r | |
129 | \r | |
130 | mix_dest_b0 = FB_A0 + (((ACC0 - FB_A0) * rvb.FB_ALPHA - FB_B0 * rvb.FB_X) >> 15);\r | |
131 | mix_dest_b1 = FB_A1 + (((ACC1 - FB_A1) * rvb.FB_ALPHA - FB_B1 * rvb.FB_X) >> 15);\r | |
132 | \r | |
133 | s_buffer(MIX_DEST_A0, mix_dest_a0);\r | |
134 | s_buffer(MIX_DEST_A1, mix_dest_a1);\r | |
135 | s_buffer(MIX_DEST_B0, mix_dest_b0);\r | |
136 | s_buffer(MIX_DEST_B1, mix_dest_b1);\r | |
137 | \r | |
b72f17a1 | 138 | l = (mix_dest_a0 + mix_dest_b0) / 2;\r |
139 | r = (mix_dest_a1 + mix_dest_b1) / 2;\r | |
1775933a | 140 | \r |
b72f17a1 | 141 | l = (l * rvb.VolLeft) >> 15; // 15?\r |
142 | r = (r * rvb.VolRight) >> 15;\r | |
143 | \r | |
144 | SSumLR[ns++] += (l + l_old) / 2;\r | |
145 | SSumLR[ns++] += (r + r_old) / 2;\r | |
146 | SSumLR[ns++] += l;\r | |
147 | SSumLR[ns++] += r;\r | |
148 | \r | |
149 | l_old = l;\r | |
150 | r_old = r;\r | |
151 | \r | |
152 | curr_addr++;\r | |
153 | if (curr_addr >= 0x40000) curr_addr = rvb.StartAddr;\r | |
154 | }\r | |
155 | \r | |
156 | rvb.iRVBLeft = l;\r | |
157 | rvb.iRVBRight = r;\r | |
158 | rvb.CurrAddr = curr_addr;\r | |
159 | }\r | |
160 | \r | |
650adfd2 | 161 | static void MixREVERB_off(int ns_to)\r |
b72f17a1 | 162 | {\r |
163 | int l_old = rvb.iRVBLeft;\r | |
164 | int r_old = rvb.iRVBRight;\r | |
165 | int curr_addr = rvb.CurrAddr;\r | |
166 | int space = 0x40000 - rvb.StartAddr;\r | |
650adfd2 | 167 | int l = 0, r = 0, ns;\r |
b72f17a1 | 168 | \r |
650adfd2 | 169 | for (ns = 0; ns < ns_to * 2; )\r |
b72f17a1 | 170 | {\r |
171 | l = (g_buffer(MIX_DEST_A0) + g_buffer(MIX_DEST_B0)) / 2;\r | |
172 | r = (g_buffer(MIX_DEST_A1) + g_buffer(MIX_DEST_B1)) / 2;\r | |
173 | \r | |
174 | l = (l * rvb.VolLeft) >> 15;\r | |
175 | r = (r * rvb.VolRight) >> 15;\r | |
1775933a | 176 | \r |
177 | SSumLR[ns++] += (l + l_old) / 2;\r | |
178 | SSumLR[ns++] += (r + r_old) / 2;\r | |
179 | SSumLR[ns++] += l;\r | |
180 | SSumLR[ns++] += r;\r | |
181 | \r | |
182 | l_old = l;\r | |
183 | r_old = r;\r | |
184 | \r | |
185 | curr_addr++;\r | |
186 | if (curr_addr >= 0x40000) curr_addr = rvb.StartAddr;\r | |
ef79bbde | 187 | }\r |
1775933a | 188 | \r |
189 | rvb.iRVBLeft = l;\r | |
190 | rvb.iRVBRight = r;\r | |
191 | rvb.CurrAddr = curr_addr;\r | |
ef79bbde P |
192 | }\r |
193 | \r | |
1775933a | 194 | static void prepare_offsets(void)\r |
195 | {\r | |
196 | int space = 0x40000 - rvb.StartAddr;\r | |
197 | int t;\r | |
198 | #define prep_offs(v) \\r | |
199 | t = rvb.v; \\r | |
200 | while (t >= space) \\r | |
201 | t -= space; \\r | |
202 | rvb.n##v = t\r | |
203 | #define prep_offs2(d, v1, v2) \\r | |
204 | t = rvb.v1 - rvb.v2; \\r | |
205 | while (t >= space) \\r | |
206 | t -= space; \\r | |
207 | rvb.n##d = t\r | |
208 | \r | |
209 | prep_offs(IIR_SRC_A0);\r | |
210 | prep_offs(IIR_SRC_A1);\r | |
211 | prep_offs(IIR_SRC_B0);\r | |
212 | prep_offs(IIR_SRC_B1);\r | |
213 | prep_offs(IIR_DEST_A0);\r | |
214 | prep_offs(IIR_DEST_A1);\r | |
215 | prep_offs(IIR_DEST_B0);\r | |
216 | prep_offs(IIR_DEST_B1);\r | |
217 | prep_offs(ACC_SRC_A0);\r | |
218 | prep_offs(ACC_SRC_A1);\r | |
219 | prep_offs(ACC_SRC_B0);\r | |
220 | prep_offs(ACC_SRC_B1);\r | |
221 | prep_offs(ACC_SRC_C0);\r | |
222 | prep_offs(ACC_SRC_C1);\r | |
223 | prep_offs(ACC_SRC_D0);\r | |
224 | prep_offs(ACC_SRC_D1);\r | |
225 | prep_offs(MIX_DEST_A0);\r | |
226 | prep_offs(MIX_DEST_A1);\r | |
227 | prep_offs(MIX_DEST_B0);\r | |
228 | prep_offs(MIX_DEST_B1);\r | |
229 | prep_offs2(FB_SRC_A0, MIX_DEST_A0, FB_SRC_A);\r | |
230 | prep_offs2(FB_SRC_A1, MIX_DEST_A1, FB_SRC_A);\r | |
231 | prep_offs2(FB_SRC_B0, MIX_DEST_B0, FB_SRC_B);\r | |
232 | prep_offs2(FB_SRC_B1, MIX_DEST_B1, FB_SRC_B);\r | |
233 | \r | |
234 | #undef prep_offs\r | |
235 | #undef prep_offs2\r | |
236 | rvb.dirty = 0;\r | |
237 | }\r | |
ef79bbde | 238 | \r |
650adfd2 | 239 | INLINE void REVERBDo(int ns_to)\r |
ef79bbde | 240 | {\r |
1775933a | 241 | if (!rvb.StartAddr) // reverb is off\r |
242 | {\r | |
243 | rvb.iRVBLeft = rvb.iRVBRight = 0;\r | |
244 | return;\r | |
245 | }\r | |
246 | \r | |
3154bfab | 247 | if (spu.spuCtrl & 0x80) // -> reverb on? oki\r |
1775933a | 248 | {\r |
b72f17a1 | 249 | if (unlikely(rvb.dirty))\r |
1775933a | 250 | prepare_offsets();\r |
251 | \r | |
650adfd2 | 252 | MixREVERB(ns_to);\r |
1775933a | 253 | }\r |
b72f17a1 | 254 | else if (rvb.VolLeft || rvb.VolRight)\r |
255 | {\r | |
256 | if (unlikely(rvb.dirty))\r | |
257 | prepare_offsets();\r | |
258 | \r | |
650adfd2 | 259 | MixREVERB_off(ns_to);\r |
b72f17a1 | 260 | }\r |
1775933a | 261 | else // -> reverb off\r |
262 | {\r | |
b72f17a1 | 263 | // reverb runs anyway\r |
650adfd2 | 264 | rvb.CurrAddr += ns_to / 2;\r |
1775933a | 265 | while (rvb.CurrAddr >= 0x40000)\r |
266 | rvb.CurrAddr -= 0x40000 - rvb.StartAddr;\r | |
267 | }\r | |
ef79bbde P |
268 | }\r |
269 | \r | |
270 | ////////////////////////////////////////////////////////////////////////\r | |
271 | \r | |
272 | #endif\r | |
273 | \r | |
274 | /*\r | |
275 | -----------------------------------------------------------------------------\r | |
276 | PSX reverb hardware notes\r | |
277 | by Neill Corlett\r | |
278 | -----------------------------------------------------------------------------\r | |
279 | \r | |
280 | Yadda yadda disclaimer yadda probably not perfect yadda well it's okay anyway\r | |
281 | yadda yadda.\r | |
282 | \r | |
283 | -----------------------------------------------------------------------------\r | |
284 | \r | |
285 | Basics\r | |
286 | ------\r | |
287 | \r | |
288 | - The reverb buffer is 22khz 16-bit mono PCM.\r | |
289 | - It starts at the reverb address given by 1DA2, extends to\r | |
290 | the end of sound RAM, and wraps back to the 1DA2 address.\r | |
291 | \r | |
292 | Setting the address at 1DA2 resets the current reverb work address.\r | |
293 | \r | |
294 | This work address ALWAYS increments every 1/22050 sec., regardless of\r | |
295 | whether reverb is enabled (bit 7 of 1DAA set).\r | |
296 | \r | |
297 | And the contents of the reverb buffer ALWAYS play, scaled by the\r | |
298 | "reverberation depth left/right" volumes (1D84/1D86).\r | |
299 | (which, by the way, appear to be scaled so 3FFF=approx. 1.0, 4000=-1.0)\r | |
300 | \r | |
301 | -----------------------------------------------------------------------------\r | |
302 | \r | |
303 | Register names\r | |
304 | --------------\r | |
305 | \r | |
306 | These are probably not their real names.\r | |
307 | These are probably not even correct names.\r | |
308 | We will use them anyway, because we can.\r | |
309 | \r | |
310 | 1DC0: FB_SRC_A (offset)\r | |
311 | 1DC2: FB_SRC_B (offset)\r | |
312 | 1DC4: IIR_ALPHA (coef.)\r | |
313 | 1DC6: ACC_COEF_A (coef.)\r | |
314 | 1DC8: ACC_COEF_B (coef.)\r | |
315 | 1DCA: ACC_COEF_C (coef.)\r | |
316 | 1DCC: ACC_COEF_D (coef.)\r | |
317 | 1DCE: IIR_COEF (coef.)\r | |
318 | 1DD0: FB_ALPHA (coef.)\r | |
319 | 1DD2: FB_X (coef.)\r | |
320 | 1DD4: IIR_DEST_A0 (offset)\r | |
321 | 1DD6: IIR_DEST_A1 (offset)\r | |
322 | 1DD8: ACC_SRC_A0 (offset)\r | |
323 | 1DDA: ACC_SRC_A1 (offset)\r | |
324 | 1DDC: ACC_SRC_B0 (offset)\r | |
325 | 1DDE: ACC_SRC_B1 (offset)\r | |
326 | 1DE0: IIR_SRC_A0 (offset)\r | |
327 | 1DE2: IIR_SRC_A1 (offset)\r | |
328 | 1DE4: IIR_DEST_B0 (offset)\r | |
329 | 1DE6: IIR_DEST_B1 (offset)\r | |
330 | 1DE8: ACC_SRC_C0 (offset)\r | |
331 | 1DEA: ACC_SRC_C1 (offset)\r | |
332 | 1DEC: ACC_SRC_D0 (offset)\r | |
333 | 1DEE: ACC_SRC_D1 (offset)\r | |
334 | 1DF0: IIR_SRC_B1 (offset)\r | |
335 | 1DF2: IIR_SRC_B0 (offset)\r | |
336 | 1DF4: MIX_DEST_A0 (offset)\r | |
337 | 1DF6: MIX_DEST_A1 (offset)\r | |
338 | 1DF8: MIX_DEST_B0 (offset)\r | |
339 | 1DFA: MIX_DEST_B1 (offset)\r | |
340 | 1DFC: IN_COEF_L (coef.)\r | |
341 | 1DFE: IN_COEF_R (coef.)\r | |
342 | \r | |
343 | The coefficients are signed fractional values.\r | |
344 | -32768 would be -1.0\r | |
345 | 32768 would be 1.0 (if it were possible... the highest is of course 32767)\r | |
346 | \r | |
347 | The offsets are (byte/8) offsets into the reverb buffer.\r | |
348 | i.e. you multiply them by 8, you get byte offsets.\r | |
349 | You can also think of them as (samples/4) offsets.\r | |
350 | They appear to be signed. They can be negative.\r | |
351 | None of the documented presets make them negative, though.\r | |
352 | \r | |
353 | Yes, 1DF0 and 1DF2 appear to be backwards. Not a typo.\r | |
354 | \r | |
355 | -----------------------------------------------------------------------------\r | |
356 | \r | |
357 | What it does\r | |
358 | ------------\r | |
359 | \r | |
360 | We take all reverb sources:\r | |
361 | - regular channels that have the reverb bit on\r | |
362 | - cd and external sources, if their reverb bits are on\r | |
363 | and mix them into one stereo 44100hz signal.\r | |
364 | \r | |
365 | Lowpass/downsample that to 22050hz. The PSX uses a proper bandlimiting\r | |
366 | algorithm here, but I haven't figured out the hysterically exact specifics.\r | |
367 | I use an 8-tap filter with these coefficients, which are nice but probably\r | |
368 | not the real ones:\r | |
369 | \r | |
370 | 0.037828187894\r | |
371 | 0.157538631280\r | |
372 | 0.321159685278\r | |
373 | 0.449322115345\r | |
374 | 0.449322115345\r | |
375 | 0.321159685278\r | |
376 | 0.157538631280\r | |
377 | 0.037828187894\r | |
378 | \r | |
379 | So we have two input samples (INPUT_SAMPLE_L, INPUT_SAMPLE_R) every 22050hz.\r | |
380 | \r | |
381 | * IN MY EMULATION, I divide these by 2 to make it clip less.\r | |
382 | (and of course the L/R output coefficients are adjusted to compensate)\r | |
383 | The real thing appears to not do this.\r | |
384 | \r | |
385 | At every 22050hz tick:\r | |
386 | - If the reverb bit is enabled (bit 7 of 1DAA), execute the reverb\r | |
387 | steady-state algorithm described below\r | |
388 | - AFTERWARDS, retrieve the "wet out" L and R samples from the reverb buffer\r | |
389 | (This part may not be exactly right and I guessed at the coefs. TODO: check later.)\r | |
390 | L is: 0.333 * (buffer[MIX_DEST_A0] + buffer[MIX_DEST_B0])\r | |
391 | R is: 0.333 * (buffer[MIX_DEST_A1] + buffer[MIX_DEST_B1])\r | |
392 | - Advance the current buffer position by 1 sample\r | |
393 | \r | |
394 | The wet out L and R are then upsampled to 44100hz and played at the\r | |
395 | "reverberation depth left/right" (1D84/1D86) volume, independent of the main\r | |
396 | volume.\r | |
397 | \r | |
398 | -----------------------------------------------------------------------------\r | |
399 | \r | |
400 | Reverb steady-state\r | |
401 | -------------------\r | |
402 | \r | |
403 | The reverb steady-state algorithm is fairly clever, and of course by\r | |
404 | "clever" I mean "batshit insane".\r | |
405 | \r | |
406 | buffer[x] is relative to the current buffer position, not the beginning of\r | |
407 | the buffer. Note that all buffer offsets must wrap around so they're\r | |
408 | contained within the reverb work area.\r | |
409 | \r | |
410 | Clipping is performed at the end... maybe also sooner, but definitely at\r | |
411 | the end.\r | |
412 | \r | |
413 | IIR_INPUT_A0 = buffer[IIR_SRC_A0] * IIR_COEF + INPUT_SAMPLE_L * IN_COEF_L;\r | |
414 | IIR_INPUT_A1 = buffer[IIR_SRC_A1] * IIR_COEF + INPUT_SAMPLE_R * IN_COEF_R;\r | |
415 | IIR_INPUT_B0 = buffer[IIR_SRC_B0] * IIR_COEF + INPUT_SAMPLE_L * IN_COEF_L;\r | |
416 | IIR_INPUT_B1 = buffer[IIR_SRC_B1] * IIR_COEF + INPUT_SAMPLE_R * IN_COEF_R;\r | |
417 | \r | |
418 | IIR_A0 = IIR_INPUT_A0 * IIR_ALPHA + buffer[IIR_DEST_A0] * (1.0 - IIR_ALPHA);\r | |
419 | IIR_A1 = IIR_INPUT_A1 * IIR_ALPHA + buffer[IIR_DEST_A1] * (1.0 - IIR_ALPHA);\r | |
420 | IIR_B0 = IIR_INPUT_B0 * IIR_ALPHA + buffer[IIR_DEST_B0] * (1.0 - IIR_ALPHA);\r | |
421 | IIR_B1 = IIR_INPUT_B1 * IIR_ALPHA + buffer[IIR_DEST_B1] * (1.0 - IIR_ALPHA);\r | |
422 | \r | |
423 | buffer[IIR_DEST_A0 + 1sample] = IIR_A0;\r | |
424 | buffer[IIR_DEST_A1 + 1sample] = IIR_A1;\r | |
425 | buffer[IIR_DEST_B0 + 1sample] = IIR_B0;\r | |
426 | buffer[IIR_DEST_B1 + 1sample] = IIR_B1;\r | |
427 | \r | |
428 | ACC0 = buffer[ACC_SRC_A0] * ACC_COEF_A +\r | |
429 | buffer[ACC_SRC_B0] * ACC_COEF_B +\r | |
430 | buffer[ACC_SRC_C0] * ACC_COEF_C +\r | |
431 | buffer[ACC_SRC_D0] * ACC_COEF_D;\r | |
432 | ACC1 = buffer[ACC_SRC_A1] * ACC_COEF_A +\r | |
433 | buffer[ACC_SRC_B1] * ACC_COEF_B +\r | |
434 | buffer[ACC_SRC_C1] * ACC_COEF_C +\r | |
435 | buffer[ACC_SRC_D1] * ACC_COEF_D;\r | |
436 | \r | |
437 | FB_A0 = buffer[MIX_DEST_A0 - FB_SRC_A];\r | |
438 | FB_A1 = buffer[MIX_DEST_A1 - FB_SRC_A];\r | |
439 | FB_B0 = buffer[MIX_DEST_B0 - FB_SRC_B];\r | |
440 | FB_B1 = buffer[MIX_DEST_B1 - FB_SRC_B];\r | |
441 | \r | |
442 | buffer[MIX_DEST_A0] = ACC0 - FB_A0 * FB_ALPHA;\r | |
443 | buffer[MIX_DEST_A1] = ACC1 - FB_A1 * FB_ALPHA;\r | |
444 | buffer[MIX_DEST_B0] = (FB_ALPHA * ACC0) - FB_A0 * (FB_ALPHA^0x8000) - FB_B0 * FB_X;\r | |
445 | buffer[MIX_DEST_B1] = (FB_ALPHA * ACC1) - FB_A1 * (FB_ALPHA^0x8000) - FB_B1 * FB_X;\r | |
446 | \r | |
447 | -----------------------------------------------------------------------------\r | |
448 | */\r | |
449 | \r | |
1775933a | 450 | // vim:shiftwidth=1:expandtab\r |