midisyn.c revision 1.18
1/* $NetBSD: midisyn.c,v 1.18 2006/06/30 13:56:25 chap Exp $ */ 2 3/* 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Lennart Augustsson (augustss@NetBSD.org). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39#include <sys/cdefs.h> 40__KERNEL_RCSID(0, "$NetBSD: midisyn.c,v 1.18 2006/06/30 13:56:25 chap Exp $"); 41 42#include <sys/param.h> 43#include <sys/ioctl.h> 44#include <sys/fcntl.h> 45#include <sys/vnode.h> 46#include <sys/select.h> 47#include <sys/proc.h> 48#include <sys/malloc.h> 49#include <sys/systm.h> 50#include <sys/syslog.h> 51#include <sys/kernel.h> 52#include <sys/audioio.h> 53#include <sys/midiio.h> 54#include <sys/device.h> 55 56#include <dev/audio_if.h> 57#include <dev/midi_if.h> 58#include <dev/midivar.h> 59#include <dev/midisynvar.h> 60 61#ifdef AUDIO_DEBUG 62#define DPRINTF(x) if (midisyndebug) printf x 63#define DPRINTFN(n,x) if (midisyndebug >= (n)) printf x 64int midisyndebug = 0; 65#else 66#define DPRINTF(x) 67#define DPRINTFN(n,x) 68#endif 69 70int midisyn_findvoice(midisyn *, int, int); 71void midisyn_freevoice(midisyn *, int); 72uint_fast16_t midisyn_allocvoice(midisyn *, uint_fast8_t, uint_fast8_t); 73static void midisyn_attackv_vel(midisyn *, uint_fast16_t, midipitch_t, 74 int16_t, uint_fast8_t); 75 76static midictl_notify midisyn_notify; 77 78static midipitch_t midisyn_clamp_pitch(midipitch_t); 79static int16_t midisyn_adj_level(midisyn *, uint_fast8_t); 80static midipitch_t midisyn_adj_pitch(midisyn *, uint_fast8_t); 81static void midisyn_chan_releasev(midisyn *, uint_fast8_t, uint_fast8_t); 82static void midisyn_upd_level(midisyn *, uint_fast8_t); 83static void midisyn_upd_pitch(midisyn *, uint_fast8_t); 84 85int midisyn_open(void *, int, 86 void (*iintr)(void *, int), 87 void (*ointr)(void *), void *arg); 88void midisyn_close(void *); 89int midisyn_sysrt(void *, int); 90void midisyn_getinfo(void *, struct midi_info *); 91int midisyn_ioctl(void *, u_long, caddr_t, int, struct lwp *); 92 93const struct midi_hw_if midisyn_hw_if = { 94 midisyn_open, 95 midisyn_close, 96 midisyn_sysrt, 97 midisyn_getinfo, 98 midisyn_ioctl, 99}; 100 101int midisyn_channelmsg(void *, int, int, u_char *, int); 102int midisyn_commonmsg(void *, int, u_char *, int); 103int midisyn_sysex(void *, u_char *, int); 104 105struct midi_hw_if_ext midisyn_hw_if_ext = { 106 .channel = midisyn_channelmsg, 107 .common = midisyn_commonmsg, 108 .sysex = midisyn_sysex, 109}; 110 111struct channelstate { /* dyamically allocated in open() on account of size */ 112 /* volume state components in centibels; just sum for overall level */ 113 int16_t volume; 114 int16_t expression; 115 /* pitch state components in midipitch units; sum for overall effect */ 116 midipitch_t bend; 117 midipitch_t tuning_fine; 118 midipitch_t tuning_coarse; 119 /* used by bend handlers */ 120 int16_t bendraw; 121 int16_t pendingreset; 122/* rearrange as more controls supported - 16 bits should last for a while */ 123#define PEND_VOL 1 124#define PEND_EXP 2 125#define PEND_LEVEL (PEND_VOL|PEND_EXP) 126#define PEND_PBS 4 127#define PEND_TNF 8 128#define PEND_TNC 16 129#define PEND_PITCH (PEND_PBS|PEND_TNF|PEND_TNC) 130#define PEND_ALL (PEND_LEVEL|PEND_PITCH) 131}; 132 133int 134midisyn_open(void *addr, int flags, void (*iintr)(void *, int), 135 void (*ointr)(void *), void *arg) 136{ 137 midisyn *ms = addr; 138 int rslt; 139 uint_fast8_t chan; 140 141 DPRINTF(("midisyn_open: ms=%p ms->mets=%p\n", ms, ms->mets)); 142 143 midictl_open(&ms->ctl); 144 145 ms->chnstate = malloc(MIDI_MAX_CHANS*sizeof *(ms->chnstate), 146 M_DEVBUF, M_WAITOK); /* init'd by RESET below */ 147 148 rslt = 0; 149 if (ms->mets->open) 150 rslt = (ms->mets->open(ms, flags)); 151 152 /* 153 * Make the right initial things happen by faking receipt of RESET on 154 * all channels. The hw driver's ctlnotice() will be called in turn. 155 */ 156 for ( chan = 0 ; chan < MIDI_MAX_CHANS ; ++ chan ) 157 midisyn_notify(ms, MIDICTL_RESET, chan, 0); 158 159 return rslt; 160} 161 162void 163midisyn_close(void *addr) 164{ 165 midisyn *ms = addr; 166 struct midisyn_methods *fs; 167 int chan; 168 169 DPRINTF(("midisyn_close: ms=%p ms->mets=%p\n", ms, ms->mets)); 170 fs = ms->mets; 171 172 for (chan = 0; chan < MIDI_MAX_CHANS; chan++) 173 midisyn_notify(ms, MIDICTL_SOUND_OFF, chan, 0); 174 175 if (fs->close) 176 fs->close(ms); 177 178 free(ms->chnstate, M_DEVBUF); 179 180 midictl_close(&ms->ctl); 181} 182 183void 184midisyn_getinfo(void *addr, struct midi_info *mi) 185{ 186 midisyn *ms = addr; 187 188 mi->name = ms->name; 189 /* 190 * I was going to add a property here to suppress midi(4)'s warning 191 * about an output device that uses no transmit interrupt, on the 192 * assumption that as an onboard synth we handle "output" internally 193 * with nothing like the 320 us per byte busy wait of a dumb UART. 194 * Then I noticed that opl (at least as currently implemented) seems 195 * to need 40 us busy wait to set each register on an OPL2, and sets 196 * about 21 registers for every note-on. (Half of that is patch loading 197 * and could probably be reduced by different management of voices and 198 * patches.) For now I won't bother suppressing that warning.... 199 */ 200 mi->props = 0; 201 202 midi_register_hw_if_ext(&midisyn_hw_if_ext); 203} 204 205int 206midisyn_ioctl(void *maddr, u_long cmd, caddr_t addr, int flag, struct lwp *l) 207{ 208 midisyn *ms = maddr; 209 210 if (ms->mets->ioctl) 211 return (ms->mets->ioctl(ms, cmd, addr, flag, l)); 212 else 213 return (EINVAL); 214} 215 216int 217midisyn_findvoice(midisyn *ms, int chan, int note) 218{ 219 u_int cn; 220 int v; 221 222 cn = MS_CHANNOTE(chan, note); 223 for (v = 0; v < ms->nvoice; v++) 224 if (ms->voices[v].chan_note == cn && ms->voices[v].inuse) 225 return (v); 226 return (-1); 227} 228 229void 230midisyn_attach(struct midi_softc *sc, midisyn *ms) 231{ 232 /* 233 * XXX there should be a way for this function to indicate failure 234 * (other than panic) if some preconditions aren't met, for example 235 * if some nonoptional methods are missing. 236 */ 237 if (ms->mets->allocv == 0) { 238 ms->voices = malloc(ms->nvoice * sizeof (struct voice), 239 M_DEVBUF, M_WAITOK|M_ZERO); 240 ms->seqno = 1; 241 ms->mets->allocv = midisyn_allocvoice; 242 } 243 244 if (ms->mets->attackv_vel == 0 && ms->mets->attackv != 0) 245 ms->mets->attackv_vel = midisyn_attackv_vel; 246 247 ms->ctl = (midictl) { 248 .base_channel = 16, 249 .cookie = ms, 250 .notify = midisyn_notify 251 }; 252 253 sc->hw_if = &midisyn_hw_if; 254 sc->hw_hdl = ms; 255 DPRINTF(("midisyn_attach: ms=%p\n", sc->hw_hdl)); 256} 257 258void 259midisyn_freevoice(midisyn *ms, int voice) 260{ 261 if (ms->mets->allocv != midisyn_allocvoice) 262 return; 263 ms->voices[voice].inuse = 0; 264} 265 266uint_fast16_t 267midisyn_allocvoice(midisyn *ms, uint_fast8_t chan, uint_fast8_t note) 268{ 269 int bestv, v; 270 u_int bestseq, s; 271 272 /* Find a free voice, or if no free voice is found the oldest. */ 273 bestv = 0; 274 bestseq = ms->voices[0].seqno + (ms->voices[0].inuse ? 0x40000000 : 0); 275 for (v = 1; v < ms->nvoice; v++) { 276 s = ms->voices[v].seqno; 277 if (ms->voices[v].inuse) 278 s += 0x40000000; 279 if (s < bestseq) { 280 bestseq = s; 281 bestv = v; 282 } 283 } 284 DPRINTFN(10,("midisyn_allocvoice: v=%d seq=%d cn=%x inuse=%d\n", 285 bestv, ms->voices[bestv].seqno, 286 ms->voices[bestv].chan_note, 287 ms->voices[bestv].inuse)); 288#ifdef AUDIO_DEBUG 289 if (ms->voices[bestv].inuse) 290 DPRINTFN(1,("midisyn_allocvoice: steal %x\n", 291 ms->voices[bestv].chan_note)); 292#endif 293 ms->voices[bestv].chan_note = MS_CHANNOTE(chan, note); 294 ms->voices[bestv].seqno = ms->seqno++; 295 ms->voices[bestv].inuse = 1; 296 return (bestv); 297} 298 299/* dummy attackv_vel that just adds vel into level for simple drivers */ 300static void 301midisyn_attackv_vel(midisyn *ms, uint_fast16_t voice, midipitch_t mp, 302 int16_t level_cB, uint_fast8_t vel) 303{ 304 ms->voices[voice].velcB = midisyn_vol2cB((uint_fast16_t)vel << 7); 305 ms->mets->attackv(ms, voice, mp, level_cB + ms->voices[voice].velcB); 306} 307 308int 309midisyn_sysrt(void *addr, int b) 310{ 311 return 0; 312} 313 314int midisyn_channelmsg(void *addr, int status, int chan, u_char *buf, int len) 315{ 316 midisyn *ms = addr; 317 int voice = 0; /* initialize to keep gcc quiet */ 318 struct midisyn_methods *fs; 319 320 DPRINTF(("midisyn_channelmsg: ms=%p status=%#02x chan=%d\n", 321 ms, status, chan)); 322 fs = ms->mets; 323 324 switch (status) { 325 case MIDI_NOTEOFF: 326 /* 327 * for a device that leaves voice allocation to us--and that's 328 * all of 'em at the moment--the voice and release velocity 329 * should be the only necessary arguments to noteoff. what use 330 * are they making of note? checking... None. Cool. 331 * IF there is ever a device added that does its own allocation, 332 * extend the interface; this findvoice won't be what to do... 333 */ 334 voice = midisyn_findvoice(ms, chan, buf[1]); 335 if (voice >= 0) { 336 fs->releasev(ms, voice, buf[2]); 337 midisyn_freevoice(ms, voice); 338 } 339 break; 340 case MIDI_NOTEON: 341 /* 342 * what's called for here, given current drivers, is an i/f 343 * where midisyn computes a volume from vel*volume*expression* 344 * mastervolume and passes that result as a single arg. It can 345 * evolve later to support drivers that expose some of those 346 * bits separately (e.g. a driver could expose a mixer register 347 * on its sound card and use that for mastervolume). 348 */ 349 voice = fs->allocv(ms, chan, buf[1]); 350 ms->voices[voice].velcB = 0; /* assume driver handles vel */ 351 fs->attackv_vel(ms, voice, 352 midisyn_clamp_pitch(MIDIPITCH_FROM_KEY(buf[1]) + 353 midisyn_adj_pitch(ms, chan)), 354 midisyn_adj_level(ms,chan), buf[2]); 355 break; 356 case MIDI_KEY_PRESSURE: 357 /* 358 * unimplemented by the existing drivers. if we are doing 359 * voice allocation, find the voice that corresponds to this 360 * chan/note and define a method that passes the voice and 361 * pressure to the driver ... not the note, /it/ doesn't matter. 362 * For a driver that does its own allocation, a different 363 * method may be needed passing pressure, chan, note so it can 364 * find the right voice on its own. Be sure that whatever is 365 * done here is undone when midisyn_notify sees MIDICTL_RESET. 366 */ 367 break; 368 case MIDI_CTL_CHANGE: 369 midictl_change(&ms->ctl, chan, buf+1); 370 break; 371 case MIDI_PGM_CHANGE: 372 if (fs->pgmchg) 373 fs->pgmchg(ms, chan, buf[1]); 374 break; 375 case MIDI_CHN_PRESSURE: 376 /* 377 * unimplemented by the existing drivers. if driver exposes no 378 * distinct method, can use KEY_PRESSURE method for each voice 379 * on channel. Be sure that whatever is 380 * done here is undone when midisyn_notify sees MIDICTL_RESET. 381 */ 382 break; 383 case MIDI_PITCH_BEND: 384 /* 385 * Will work for most drivers that simply render the midipitch 386 * as we pass it (but not cms, which chops all the bits after 387 * the note number and then computes its own pitch :( ). If the 388 * driver has a repitchv method for voices already sounding, so 389 * much the better. 390 * The bending logic lives in the handler for bend sensitivity, 391 * so fake a change to that to kick it off. 392 */ 393 ms->chnstate[chan].bendraw = buf[2]<<7 | buf[1]; 394 ms->chnstate[chan].bendraw -= MIDI_BEND_NEUTRAL; 395 midisyn_notify(ms, MIDICTL_RPN, chan, 396 MIDI_RPN_PITCH_BEND_SENSITIVITY); 397 break; 398 } 399 return 0; 400} 401 402int midisyn_commonmsg(void *addr, int status, u_char *buf, int len) 403{ 404 return 0; 405} 406 407int midisyn_sysex(void *addr, u_char *buf, int len) 408{ 409 /* 410 * unimplemented by existing drivers. it is surely more sensible 411 * to do some parsing of well-defined sysex messages here, either 412 * handling them internally or calling specific methods on the 413 * driver after parsing out the details, than to ask every driver 414 * to deal with sysex messages poked at it a byte at a time. 415 */ 416 return 0; 417} 418 419static void 420midisyn_notify(void *cookie, midictl_evt evt, 421 uint_fast8_t chan, uint_fast16_t key) 422{ 423 struct midisyn *ms; 424 int drvhandled; 425 426 ms = (struct midisyn *)cookie; 427 drvhandled = 0; 428 if ( ms->mets->ctlnotice ) 429 drvhandled = ms->mets->ctlnotice(ms, evt, chan, key); 430 431 switch ( evt | key ) { 432 case MIDICTL_RESET: 433 /* 434 * Re-read all ctls we use, revert pitchbend state. 435 * Can do it by faking change notifications. 436 */ 437 ms->chnstate[chan].pendingreset |= PEND_ALL; 438 midisyn_notify(ms, MIDICTL_CTLR, chan, 439 MIDI_CTRL_CHANNEL_VOLUME_MSB); 440 midisyn_notify(ms, MIDICTL_CTLR, chan, 441 MIDI_CTRL_EXPRESSION_MSB); 442 ms->chnstate[chan].bendraw = 0; /* MIDI_BEND_NEUTRAL - itself */ 443 midisyn_notify(ms, MIDICTL_RPN, chan, 444 MIDI_RPN_PITCH_BEND_SENSITIVITY); 445 midisyn_notify(ms, MIDICTL_RPN, chan, 446 MIDI_RPN_CHANNEL_FINE_TUNING); 447 midisyn_notify(ms, MIDICTL_RPN, chan, 448 MIDI_RPN_CHANNEL_COARSE_TUNING); 449 break; 450 case MIDICTL_NOTES_OFF: 451 if ( drvhandled ) 452 break; 453 /* releasev all voices sounding on chan; use normal vel 64 */ 454 midisyn_chan_releasev(ms, chan, 64); 455 break; 456 case MIDICTL_SOUND_OFF: 457 if ( drvhandled ) 458 break; 459 /* releasev all voices sounding on chan; use max vel 127 */ 460 /* it is really better for driver to handle this, instantly */ 461 midisyn_chan_releasev(ms, chan, 127); 462 break; 463 case MIDICTL_CTLR | MIDI_CTRL_CHANNEL_VOLUME_MSB: 464 ms->chnstate[chan].pendingreset &= ~PEND_VOL; 465 if ( drvhandled ) { 466 ms->chnstate[chan].volume = 0; 467 break; 468 } 469 ms->chnstate[chan].volume = midisyn_vol2cB( 470 midictl_read(&ms->ctl, chan, key, 100<<7)); 471 midisyn_upd_level(ms, chan); 472 break; 473 case MIDICTL_CTLR | MIDI_CTRL_EXPRESSION_MSB: 474 ms->chnstate[chan].pendingreset &= ~PEND_EXP; 475 if ( drvhandled ) { 476 ms->chnstate[chan].expression = 0; 477 break; 478 } 479 ms->chnstate[chan].expression = midisyn_vol2cB( 480 midictl_read(&ms->ctl, chan, key, 16383)); 481 midisyn_upd_level(ms, chan); 482 break; 483 /* 484 * SOFT_PEDAL: supporting this will be trickier; must apply only 485 * to notes subsequently struck, and must remember which voices 486 * they are for follow-on adjustments. For another day.... 487 */ 488 case MIDICTL_RPN | MIDI_RPN_PITCH_BEND_SENSITIVITY: 489 ms->chnstate[chan].pendingreset &= ~PEND_PBS; 490 if ( drvhandled ) 491 ms->chnstate[chan].bend = 0; 492 else { 493 uint16_t w; 494 int8_t semis, cents; 495 w = midictl_rpn_read(&ms->ctl, chan, key, 2<<7); 496 semis = w>>7; 497 cents = w&0x7f; 498 /* 499 * Mathematically, multiply semis by 500 * MIDIPITCH_SEMITONE*bendraw/8192. Practically, avoid 501 * shifting significant bits off by observing that 502 * MIDIPITCH_SEMITONE == 1<<14 and 8192 == 1<<13, so 503 * just take semis*bendraw<<1. Do the same with cents 504 * except <<1 becomes /50 (but rounded). 505 */ 506 ms->chnstate[chan].bend = 507 ( ms->chnstate[chan].bendraw * semis ) << 1; 508 ms->chnstate[chan].bend += 509 ((ms->chnstate[chan].bendraw * cents)/25 + 1) >> 1; 510 midisyn_upd_pitch(ms, chan); 511 } 512 break; 513 case MIDICTL_RPN | MIDI_RPN_CHANNEL_FINE_TUNING: 514 if ( drvhandled ) 515 ms->chnstate[chan].tuning_fine = 0; 516 else { 517 midipitch_t mp; 518 mp = midictl_rpn_read(&ms->ctl, chan, key, 8192); 519 /* 520 * Mathematically, subtract 8192 and scale by 521 * MIDIPITCH_SEMITONE/8192. Practically, subtract 8192 522 * and then << 1. 523 */ 524 ms->chnstate[chan].tuning_fine = ( mp - 8192 ) << 1; 525 midisyn_upd_pitch(ms, chan); 526 } 527 break; 528 case MIDICTL_RPN | MIDI_RPN_CHANNEL_COARSE_TUNING: 529 ms->chnstate[chan].pendingreset &= ~PEND_TNC; 530 if ( drvhandled ) 531 ms->chnstate[chan].tuning_coarse = 0; 532 else { 533 midipitch_t mp; 534 /* 535 * By definition only the MSB of this parameter is used. 536 * Subtract 64 for a signed count of semitones; << 14 537 * will convert to midipitch scale. 538 */ 539 mp = midictl_rpn_read(&ms->ctl, chan, key, 64<<7) >> 7; 540 ms->chnstate[chan].tuning_coarse = ( mp - 64 ) << 14; 541 midisyn_upd_pitch(ms, chan); 542 } 543 break; 544 } 545} 546 547static midipitch_t 548midisyn_clamp_pitch(midipitch_t mp) 549{ 550 if ( mp <= 0 ) 551 return 0; 552 if ( mp >= MIDIPITCH_MAX ) 553 return MIDIPITCH_MAX; 554 return mp; 555} 556 557static int16_t 558midisyn_adj_level(midisyn *ms, uint_fast8_t chan) 559{ 560 int32_t level; 561 562 level = ms->chnstate[chan].volume + ms->chnstate[chan].expression; 563 if ( level <= INT16_MIN ) 564 return INT16_MIN; 565 return level; 566} 567 568static midipitch_t 569midisyn_adj_pitch(midisyn *ms, uint_fast8_t chan) 570{ 571 struct channelstate *s = ms->chnstate + chan; 572 return s->bend + s->tuning_fine +s->tuning_coarse; 573} 574 575#define VOICECHAN_FOREACH_BEGIN(ms,vp,ch) \ 576 { \ 577 struct voice *vp, *_end_##vp; \ 578 for (vp=(ms)->voices,_end_##vp=vp+(ms)->nvoice; \ 579 vp < _end_##vp; ++ vp) { \ 580 if ( !vp->inuse ) \ 581 continue; \ 582 if ( MS_GETCHAN(vp) == (ch) ) \ 583 ; \ 584 else \ 585 continue; 586#define VOICECHAN_FOREACH_END }} 587 588static void 589midisyn_chan_releasev(midisyn *ms, uint_fast8_t chan, uint_fast8_t vel) 590{ 591 VOICECHAN_FOREACH_BEGIN(ms,vp,chan) 592 ms->mets->releasev(ms, vp - ms->voices, vel); 593 midisyn_freevoice(ms, vp - ms->voices); 594 VOICECHAN_FOREACH_END 595} 596 597static void 598midisyn_upd_level(midisyn *ms, uint_fast8_t chan) 599{ 600 int32_t level; 601 int16_t chan_level; 602 if ( NULL == ms->mets->relevelv ) 603 return; 604 605 if ( ms->chnstate[chan].pendingreset & PEND_LEVEL ) 606 return; 607 608 chan_level = midisyn_adj_level(ms, chan); 609 610 VOICECHAN_FOREACH_BEGIN(ms,vp,chan) 611 level = vp->velcB + chan_level; 612 ms->mets->relevelv(ms, vp - ms->voices, 613 level <= INT16_MIN ? INT16_MIN : level); 614 VOICECHAN_FOREACH_END 615} 616 617static void 618midisyn_upd_pitch(midisyn *ms, uint_fast8_t chan) 619{ 620 midipitch_t chan_adj; 621 622 if ( NULL == ms->mets->repitchv ) 623 return; 624 625 if ( ms->chnstate[chan].pendingreset & PEND_PITCH ) 626 return; 627 628 chan_adj = midisyn_adj_pitch(ms, chan); 629 630 VOICECHAN_FOREACH_BEGIN(ms,vp,chan) 631 ms->mets->repitchv(ms, vp - ms->voices, 632 midisyn_clamp_pitch(chan_adj + 633 MIDIPITCH_FROM_KEY(vp->chan_note&0x7f))); 634 VOICECHAN_FOREACH_END 635} 636 637#undef VOICECHAN_FOREACH_END 638#undef VOICECHAN_FOREACH_BEGIN 639 640int16_t 641midisyn_vol2cB(uint_fast16_t vol) 642{ 643 int16_t cB = 0; 644 int32_t v; 645 646 if ( 0 == vol ) 647 return INT16_MIN; 648 /* 649 * Adjust vol to fall in the range 8192..16383. Each doubling is 650 * worth 12 dB. 651 */ 652 while ( vol < 8192 ) { 653 vol <<= 1; 654 cB -= 120; 655 } 656 v = vol; /* ensure evaluation in signed 32 bit below */ 657 /* 658 * The GM vol-to-dB formula is dB = 40 log ( v / 127 ) for 7-bit v. 659 * The vol and expression controllers are in 14-bit space so the 660 * equivalent is 40 log ( v / 16256 ) - that is, MSB 127 LSB 0 because 661 * the LSB is commonly unused. MSB 127 LSB 127 would then be a tiny 662 * bit over. 663 * 1 dB resolution is a little coarser than we'd like, so let's shoot 664 * for centibels, i.e. 400 log ( v / 16256 ), and shift everything left 665 * as far as will fit in 32 bits, which turns out to be a shift of 22. 666 * This minimax polynomial approximation is good to about a centibel 667 * on the range 8192..16256, a shade worse (1.4 or so) above that. 668 * 26385/10166 is the 6th convergent of the coefficient for v^2. 669 */ 670 cB += ( v * ( 124828 - ( v * 26385 ) / 10166 ) - 1347349038 ) >> 22; 671 return cB; 672} 673 674/* 675 * MIDI RP-012 constitutes a MIDI Tuning Specification. The units are 676 * fractional-MIDIkeys, that is, the key number 00 - 7f left shifted 677 * 14 bits to provide a 14-bit fraction that divides each semitone. The 678 * whole thing is just a 21-bit number that is bent and tuned simply by 679 * adding and subtracting--the same offset is the same pitch change anywhere 680 * on the scale. One downside is that a cent is 163.84 of these units, so 681 * you can't expect a lengthy integer sum of cents to come out in tune; if you 682 * do anything in cents it is best to use them only for local adjustment of 683 * a pitch. 684 * 685 * This function converts a pitch in MIDItune units to Hz left-shifted 18 bits. 686 * That should leave you enough to shift down to whatever precision the hardware 687 * supports. 688 * 689 * Its prototype is exposed in <sys/midiio.h>. 690 */ 691midihz18_t 692midisyn_mp2hz18(midipitch_t mp) 693{ 694 int64_t t64a, t64b; 695 uint_fast8_t shift; 696 697 /* 698 * Scale from the logarithmic MIDI-Tuning units to Hz<<18. Uses the 699 * continued-fraction form of a 2/2 rational function derived to 700 * cover the highest octave (mt 1900544..2097151 or 74.00.00..7f.7f.7f 701 * in RP-012-speak, the dotted bits are 7 wide) to produce Hz shifted 702 * left just as far as the maximum Hz will fit in a uint32, which 703 * turns out to be 18. Just shift off the result for lower octaves. 704 * Fit is within 1/4 MIDI tuning unit throughout (disclaimer: the 705 * comparison relied on the double-precision log in libm). 706 */ 707 708 if ( 0 == mp ) 709 return 2143236; 710 711 for ( shift = 0; mp < 1900544; ++ shift ) 712 mp += MIDIPITCH_OCTAVE; 713 714 if ( 1998848 == mp ) 715 return UINT32_C(2463438621) >> shift; 716 717 t64a = 0x5a1a0ee4; /* INT64_C(967879298788) gcc333: spurious warning */ 718 t64a |= (int64_t)0xe1 << 32; 719 t64a /= mp - 1998848; /* here's why 1998848 is special-cased above ;) */ 720 t64a += mp - 3704981; 721 t64b = 0x6763759d; /* INT64_C(8405905567872413) goofy warning again */ 722 t64b |= (int64_t)0x1ddd20 << 32; 723 t64b /= t64a; 724 t64b += UINT32_C(2463438619); 725 return (uint32_t)t64b >> shift; 726} 727