1/*	$NetBSD: midisyn.c,v 1.25 2019/05/08 13:40:17 isaki Exp $	*/
2
3/*
4 * Copyright (c) 1998, 2008 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), and by Andrew Doran.
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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: midisyn.c,v 1.25 2019/05/08 13:40:17 isaki Exp $");
34
35#include <sys/param.h>
36#include <sys/ioctl.h>
37#include <sys/fcntl.h>
38#include <sys/vnode.h>
39#include <sys/select.h>
40#include <sys/proc.h>
41#include <sys/kmem.h>
42#include <sys/systm.h>
43#include <sys/syslog.h>
44#include <sys/kernel.h>
45#include <sys/audioio.h>
46#include <sys/midiio.h>
47#include <sys/device.h>
48
49#include <dev/audio/audio_if.h>
50#include <dev/midi_if.h>
51#include <dev/midivar.h>
52#include <dev/midisynvar.h>
53
54#ifdef AUDIO_DEBUG
55#define DPRINTF(x)	if (midisyndebug) printf x
56#define DPRINTFN(n,x)	if (midisyndebug >= (n)) printf x
57int	midisyndebug = 0;
58#else
59#define DPRINTF(x)
60#define DPRINTFN(n,x)
61#endif
62
63static int	midisyn_findvoice(midisyn *, int, int);
64static void	midisyn_freevoice(midisyn *, int);
65static uint_fast16_t	midisyn_allocvoice(midisyn *, uint_fast8_t, uint_fast8_t);
66static void	midisyn_attackv_vel(midisyn *, uint_fast16_t, midipitch_t,
67                                    int16_t, uint_fast8_t);
68
69static midictl_notify midisyn_notify;
70
71static midipitch_t midisyn_clamp_pitch(midipitch_t);
72static int16_t midisyn_adj_level(midisyn *, uint_fast8_t);
73static midipitch_t midisyn_adj_pitch(midisyn *, uint_fast8_t);
74static void midisyn_chan_releasev(midisyn *, uint_fast8_t, uint_fast8_t);
75static void midisyn_upd_level(midisyn *, uint_fast8_t);
76static void midisyn_upd_pitch(midisyn *, uint_fast8_t);
77
78static int	midisyn_open(void *, int,
79			     void (*iintr)(void *, int),
80			     void (*ointr)(void *), void *arg);
81static void	midisyn_close(void *);
82static int	midisyn_sysrt(void *, int);
83static void	midisyn_getinfo(void *, struct midi_info *);
84static int	midisyn_ioctl(void *, u_long, void *, int, struct lwp *);
85static void	midisyn_get_locks(void *, kmutex_t **, kmutex_t **);
86
87const struct midi_hw_if midisyn_hw_if = {
88	midisyn_open,
89	midisyn_close,
90	midisyn_sysrt,
91	midisyn_getinfo,
92	midisyn_ioctl,
93	midisyn_get_locks,
94};
95
96static int	midisyn_channelmsg(void *, int, int, u_char *, int);
97static int	midisyn_commonmsg(void *, int, u_char *, int);
98static int	midisyn_sysex(void *, u_char *, int);
99
100struct midi_hw_if_ext midisyn_hw_if_ext = {
101	.channel = midisyn_channelmsg,
102	.common  = midisyn_commonmsg,
103	.sysex   = midisyn_sysex,
104};
105
106struct channelstate { /* dyamically allocated in open() on account of size */
107	/* volume state components in centibels; just sum for overall level */
108	int16_t volume;
109	int16_t expression;
110	/* pitch state components in midipitch units; sum for overall effect */
111	midipitch_t bend;
112	midipitch_t tuning_fine;
113	midipitch_t tuning_coarse;
114	/* used by bend handlers */
115	int16_t bendraw;
116	int16_t pendingreset;
117/* rearrange as more controls supported - 16 bits should last for a while */
118#define PEND_VOL 1
119#define PEND_EXP 2
120#define PEND_LEVEL (PEND_VOL|PEND_EXP)
121#define PEND_PBS 4
122#define PEND_TNF 8
123#define PEND_TNC 16
124#define PEND_PITCH (PEND_PBS|PEND_TNF|PEND_TNC)
125#define PEND_ALL   (PEND_LEVEL|PEND_PITCH)
126};
127
128static int
129midisyn_open(void *addr, int flags, void (*iintr)(void *, int),
130    void (*ointr)(void *), void *arg)
131{
132	midisyn *ms = addr;
133	int rslt, error;
134	uint_fast8_t chan;
135
136	KASSERT(ms->lock != NULL);
137	KASSERT(mutex_owned(ms->lock));
138	DPRINTF(("midisyn_open: ms=%p ms->mets=%p\n", ms, ms->mets));
139
140	mutex_exit(ms->lock);
141	ms->ctl.lock = ms->lock;
142	error = midictl_open(&ms->ctl);
143	if (error != 0) {
144		mutex_enter(ms->lock);
145		return error;
146	}
147	ms->chnstate = kmem_alloc(MIDI_MAX_CHANS * sizeof(*ms->chnstate),
148	    KM_SLEEP); /* init'd by RESET below */
149	mutex_enter(ms->lock);
150
151	rslt = 0;
152	if (ms->mets->open)
153		rslt = (ms->mets->open(ms, flags));
154
155	/*
156	 * Make the right initial things happen by faking receipt of RESET on
157	 * all channels. The hw driver's ctlnotice() will be called in turn.
158	 */
159	for ( chan = 0 ; chan < MIDI_MAX_CHANS ; ++ chan )
160		midisyn_notify(ms, MIDICTL_RESET, chan, 0);
161
162	return rslt;
163}
164
165static void
166midisyn_close(void *addr)
167{
168	midisyn *ms = addr;
169	struct midisyn_methods *fs;
170	int chan;
171
172	KASSERT(mutex_owned(ms->lock));
173	DPRINTF(("midisyn_close: ms=%p ms->mets=%p\n", ms, ms->mets));
174	fs = ms->mets;
175
176	for (chan = 0; chan < MIDI_MAX_CHANS; chan++)
177		midisyn_notify(ms, MIDICTL_SOUND_OFF, chan, 0);
178
179	if (fs->close)
180		fs->close(ms);
181
182	mutex_exit(ms->lock);
183	midictl_close(&ms->ctl);
184	kmem_free(ms->chnstate, MIDI_MAX_CHANS * sizeof(*ms->chnstate));
185	mutex_enter(ms->lock);
186}
187
188static void
189midisyn_getinfo(void *addr, struct midi_info *mi)
190{
191	midisyn *ms = addr;
192
193	KASSERT(mutex_owned(ms->lock));
194
195	mi->name = ms->name;
196	/*
197	 * I was going to add a property here to suppress midi(4)'s warning
198	 * about an output device that uses no transmit interrupt, on the
199	 * assumption that as an onboard synth we handle "output" internally
200	 * with nothing like the 320 us per byte busy wait of a dumb UART.
201	 * Then I noticed that opl (at least as currently implemented) seems
202	 * to need 40 us busy wait to set each register on an OPL2, and sets
203	 * about 21 registers for every note-on. (Half of that is patch loading
204	 * and could probably be reduced by different management of voices and
205	 * patches.) For now I won't bother suppressing that warning....
206	 */
207	mi->props = 0;
208
209	midi_register_hw_if_ext(&midisyn_hw_if_ext);
210}
211
212static void
213midisyn_get_locks(void *addr, kmutex_t **intr, kmutex_t **proc)
214{
215	midisyn *ms = addr;
216
217	*intr = ms->lock;
218	*proc = NULL;
219}
220
221static int
222midisyn_ioctl(void *maddr, u_long cmd, void *addr, int flag, struct lwp *l)
223{
224	midisyn *ms = maddr;
225
226	KASSERT(mutex_owned(ms->lock));
227
228	if (ms->mets->ioctl)
229		return (ms->mets->ioctl(ms, cmd, addr, flag, l));
230	else
231		return (EINVAL);
232}
233
234static int
235midisyn_findvoice(midisyn *ms, int chan, int note)
236{
237	u_int cn;
238	int v;
239
240	KASSERT(mutex_owned(ms->lock));
241
242	cn = MS_CHANNOTE(chan, note);
243	for (v = 0; v < ms->nvoice; v++)
244		if (ms->voices[v].chan_note == cn && ms->voices[v].inuse)
245			return (v);
246	return (-1);
247}
248
249void
250midisyn_init(midisyn *ms)
251{
252
253	KASSERT(ms->lock != NULL);
254
255	/*
256	 * XXX there should be a way for this function to indicate failure
257	 * (other than panic) if some preconditions aren't met, for example
258	 * if some nonoptional methods are missing.
259	 */
260	if (ms->mets->allocv == 0) {
261		ms->voices = kmem_zalloc(ms->nvoice * sizeof(struct voice),
262		    KM_SLEEP);
263		ms->seqno = 1;
264		ms->mets->allocv = midisyn_allocvoice;
265	}
266
267	if (ms->mets->attackv_vel == 0 && ms->mets->attackv != 0)
268		ms->mets->attackv_vel = midisyn_attackv_vel;
269
270	ms->ctl = (midictl) {
271		.base_channel = 16,
272		.cookie = ms,
273		.notify = midisyn_notify
274	};
275
276	DPRINTF(("midisyn_init: ms=%p\n", ms));
277}
278
279static void
280midisyn_freevoice(midisyn *ms, int voice)
281{
282
283	KASSERT(mutex_owned(ms->lock));
284
285	if (ms->mets->allocv != midisyn_allocvoice)
286		return;
287	ms->voices[voice].inuse = 0;
288}
289
290static uint_fast16_t
291midisyn_allocvoice(midisyn *ms, uint_fast8_t chan, uint_fast8_t note)
292{
293	int bestv, v;
294	u_int bestseq, s;
295
296	KASSERT(mutex_owned(ms->lock));
297
298	/* Find a free voice, or if no free voice is found the oldest. */
299	bestv = 0;
300	bestseq = ms->voices[0].seqno + (ms->voices[0].inuse ? 0x40000000 : 0);
301	for (v = 1; v < ms->nvoice; v++) {
302		s = ms->voices[v].seqno;
303		if (ms->voices[v].inuse)
304			s += 0x40000000;
305		if (s < bestseq) {
306			bestseq = s;
307			bestv = v;
308		}
309	}
310	DPRINTFN(10,("midisyn_allocvoice: v=%d seq=%d cn=%x inuse=%d\n",
311		     bestv, ms->voices[bestv].seqno,
312		     ms->voices[bestv].chan_note,
313		     ms->voices[bestv].inuse));
314#ifdef AUDIO_DEBUG
315	if (ms->voices[bestv].inuse)
316		DPRINTFN(1,("midisyn_allocvoice: steal %x\n",
317			    ms->voices[bestv].chan_note));
318#endif
319	ms->voices[bestv].chan_note = MS_CHANNOTE(chan, note);
320	ms->voices[bestv].seqno = ms->seqno++;
321	ms->voices[bestv].inuse = 1;
322	return (bestv);
323}
324
325/* dummy attackv_vel that just adds vel into level for simple drivers */
326static void
327midisyn_attackv_vel(midisyn *ms, uint_fast16_t voice, midipitch_t mp,
328                    int16_t level_cB, uint_fast8_t vel)
329{
330
331	KASSERT(mutex_owned(ms->lock));
332
333	ms->voices[voice].velcB = midisyn_vol2cB((uint_fast16_t)vel << 7);
334	ms->mets->attackv(ms, voice, mp, level_cB + ms->voices[voice].velcB);
335}
336
337static int
338midisyn_sysrt(void *addr, int b)
339{
340
341	return 0;
342}
343
344static int
345midisyn_channelmsg(void *addr, int status, int chan, u_char *buf, int len)
346{
347	midisyn *ms = addr;
348	int voice = 0;		/* initialize to keep gcc quiet */
349	struct midisyn_methods *fs;
350
351	KASSERT(mutex_owned(ms->lock));
352
353	DPRINTF(("midisyn_channelmsg: ms=%p status=%#02x chan=%d\n",
354	       ms, status, chan));
355	fs = ms->mets;
356
357	switch (status) {
358	case MIDI_NOTEOFF:
359		/*
360		 * for a device that leaves voice allocation to us--and that's
361		 * all of 'em at the moment--the voice and release velocity
362		 * should be the only necessary arguments to noteoff. what use
363		 * are they making of note? checking... None. Cool.
364		 * IF there is ever a device added that does its own allocation,
365		 * extend the interface; this findvoice won't be what to do...
366		 */
367		voice = midisyn_findvoice(ms, chan, buf[1]);
368		if (voice >= 0) {
369			fs->releasev(ms, voice, buf[2]);
370			midisyn_freevoice(ms, voice);
371		}
372		break;
373	case MIDI_NOTEON:
374		/*
375		 * what's called for here, given current drivers, is an i/f
376		 * where midisyn computes a volume from vel*volume*expression*
377		 * mastervolume and passes that result as a single arg. It can
378		 * evolve later to support drivers that expose some of those
379		 * bits separately (e.g. a driver could expose a mixer register
380		 * on its sound card and use that for mastervolume).
381		 */
382		voice = fs->allocv(ms, chan, buf[1]);
383		ms->voices[voice].velcB = 0; /* assume driver handles vel */
384		fs->attackv_vel(ms, voice,
385		    midisyn_clamp_pitch(MIDIPITCH_FROM_KEY(buf[1]) +
386		                        midisyn_adj_pitch(ms, chan)),
387		    midisyn_adj_level(ms,chan), buf[2]);
388		break;
389	case MIDI_KEY_PRESSURE:
390		/*
391		 * unimplemented by the existing drivers. if we are doing
392		 * voice allocation, find the voice that corresponds to this
393		 * chan/note and define a method that passes the voice and
394		 * pressure to the driver ... not the note, /it/ doesn't matter.
395		 * For a driver that does its own allocation, a different
396		 * method may be needed passing pressure, chan, note so it can
397		 * find the right voice on its own. Be sure that whatever is
398		 * done here is undone when midisyn_notify sees MIDICTL_RESET.
399		 */
400		break;
401	case MIDI_CTL_CHANGE:
402		midictl_change(&ms->ctl, chan, buf+1);
403		break;
404	case MIDI_PGM_CHANGE:
405		if (fs->pgmchg)
406			fs->pgmchg(ms, chan, buf[1]);
407		break;
408	case MIDI_CHN_PRESSURE:
409		/*
410		 * unimplemented by the existing drivers. if driver exposes no
411		 * distinct method, can use KEY_PRESSURE method for each voice
412		 * on channel. Be sure that whatever is
413		 * done here is undone when midisyn_notify sees MIDICTL_RESET.
414		 */
415		break;
416	case MIDI_PITCH_BEND:
417		/*
418		 * Will work for most drivers that simply render the midipitch
419		 * as we pass it (but not cms, which chops all the bits after
420		 * the note number and then computes its own pitch :( ). If the
421		 * driver has a repitchv method for voices already sounding, so
422		 * much the better.
423		 * The bending logic lives in the handler for bend sensitivity,
424		 * so fake a change to that to kick it off.
425		 */
426		ms->chnstate[chan].bendraw = buf[2]<<7 | buf[1];
427		ms->chnstate[chan].bendraw -= MIDI_BEND_NEUTRAL;
428		midisyn_notify(ms, MIDICTL_RPN, chan,
429		               MIDI_RPN_PITCH_BEND_SENSITIVITY);
430		break;
431	}
432	return 0;
433}
434
435static int
436midisyn_commonmsg(void *addr, int status, u_char *buf, int len)
437{
438
439	return 0;
440}
441
442static int
443midisyn_sysex(void *addr, u_char *buf, int len)
444{
445
446	/*
447	 * unimplemented by existing drivers. it is surely more sensible
448	 * to do some parsing of well-defined sysex messages here, either
449	 * handling them internally or calling specific methods on the
450	 * driver after parsing out the details, than to ask every driver
451	 * to deal with sysex messages poked at it a byte at a time.
452	 */
453	return 0;
454}
455
456static void
457midisyn_notify(void *cookie, midictl_evt evt,
458               uint_fast8_t chan, uint_fast16_t key)
459{
460	struct midisyn *ms;
461	int drvhandled;
462
463	ms = (struct midisyn *)cookie;
464
465	KASSERT(mutex_owned(ms->lock));
466
467	drvhandled = 0;
468	if ( ms->mets->ctlnotice )
469		drvhandled = ms->mets->ctlnotice(ms, evt, chan, key);
470
471	switch ( evt | key ) {
472	case MIDICTL_RESET:
473		/*
474		 * Re-read all ctls we use, revert pitchbend state.
475		 * Can do it by faking change notifications.
476		 */
477		ms->chnstate[chan].pendingreset |= PEND_ALL;
478		midisyn_notify(ms, MIDICTL_CTLR, chan,
479		               MIDI_CTRL_CHANNEL_VOLUME_MSB);
480		midisyn_notify(ms, MIDICTL_CTLR, chan,
481		               MIDI_CTRL_EXPRESSION_MSB);
482		ms->chnstate[chan].bendraw = 0; /* MIDI_BEND_NEUTRAL - itself */
483		midisyn_notify(ms, MIDICTL_RPN, chan,
484		               MIDI_RPN_PITCH_BEND_SENSITIVITY);
485		midisyn_notify(ms, MIDICTL_RPN, chan,
486		               MIDI_RPN_CHANNEL_FINE_TUNING);
487		midisyn_notify(ms, MIDICTL_RPN, chan,
488		               MIDI_RPN_CHANNEL_COARSE_TUNING);
489		break;
490	case MIDICTL_NOTES_OFF:
491		if ( drvhandled )
492			break;
493		/* releasev all voices sounding on chan; use normal vel 64 */
494		midisyn_chan_releasev(ms, chan, 64);
495		break;
496	case MIDICTL_SOUND_OFF:
497		if ( drvhandled )
498			break;
499		/* releasev all voices sounding on chan; use max vel 127 */
500		/* it is really better for driver to handle this, instantly */
501		midisyn_chan_releasev(ms, chan, 127);
502		break;
503	case MIDICTL_CTLR | MIDI_CTRL_CHANNEL_VOLUME_MSB:
504		ms->chnstate[chan].pendingreset &= ~PEND_VOL;
505		if ( drvhandled ) {
506			ms->chnstate[chan].volume = 0;
507			break;
508		}
509		ms->chnstate[chan].volume = midisyn_vol2cB(
510	    	    midictl_read(&ms->ctl, chan, key, 100<<7));
511		midisyn_upd_level(ms, chan);
512		break;
513	case MIDICTL_CTLR | MIDI_CTRL_EXPRESSION_MSB:
514		ms->chnstate[chan].pendingreset &= ~PEND_EXP;
515		if ( drvhandled ) {
516			ms->chnstate[chan].expression = 0;
517			break;
518		}
519		ms->chnstate[chan].expression = midisyn_vol2cB(
520	    	    midictl_read(&ms->ctl, chan, key, 16383));
521		midisyn_upd_level(ms, chan);
522		break;
523	/*
524	 * SOFT_PEDAL: supporting this will be trickier; must apply only
525	 * to notes subsequently struck, and must remember which voices
526	 * they are for follow-on adjustments. For another day....
527	 */
528	case MIDICTL_RPN | MIDI_RPN_PITCH_BEND_SENSITIVITY:
529		ms->chnstate[chan].pendingreset &= ~PEND_PBS;
530		if ( drvhandled )
531			ms->chnstate[chan].bend = 0;
532		else {
533			uint16_t w;
534			int8_t semis, cents;
535			w = midictl_rpn_read(&ms->ctl, chan, key, 2<<7);
536			semis = w>>7;
537			cents = w&0x7f;
538			/*
539			 * Mathematically, multiply semis by
540			 * MIDIPITCH_SEMITONE*bendraw/8192. Practically, avoid
541			 * shifting significant bits off by observing that
542			 * MIDIPITCH_SEMITONE == 1<<14 and 8192 == 1<<13, so
543			 * just take semis*bendraw<<1. Do the same with cents
544			 * except <<1 becomes /50 (but rounded).
545			 */
546			ms->chnstate[chan].bend =
547			    ( ms->chnstate[chan].bendraw * semis ) << 1;
548			ms->chnstate[chan].bend +=
549			    ((ms->chnstate[chan].bendraw * cents)/25 + 1) >> 1;
550			midisyn_upd_pitch(ms, chan);
551		}
552		break;
553	case MIDICTL_RPN | MIDI_RPN_CHANNEL_FINE_TUNING:
554		if ( drvhandled )
555			ms->chnstate[chan].tuning_fine = 0;
556		else {
557			midipitch_t mp;
558			mp = midictl_rpn_read(&ms->ctl, chan, key, 8192);
559			/*
560			 * Mathematically, subtract 8192 and scale by
561			 * MIDIPITCH_SEMITONE/8192. Practically, subtract 8192
562			 * and then << 1.
563			 */
564			ms->chnstate[chan].tuning_fine = ( mp - 8192 ) << 1;
565			midisyn_upd_pitch(ms, chan);
566		}
567		break;
568	case MIDICTL_RPN | MIDI_RPN_CHANNEL_COARSE_TUNING:
569		ms->chnstate[chan].pendingreset &= ~PEND_TNC;
570		if ( drvhandled )
571			ms->chnstate[chan].tuning_coarse = 0;
572		else {
573			midipitch_t mp;
574			/*
575			 * By definition only the MSB of this parameter is used.
576			 * Subtract 64 for a signed count of semitones; << 14
577			 * will convert to midipitch scale.
578			 */
579			mp = midictl_rpn_read(&ms->ctl, chan, key, 64<<7) >> 7;
580			ms->chnstate[chan].tuning_coarse = ( mp - 64 ) << 14;
581			midisyn_upd_pitch(ms, chan);
582		}
583		break;
584	}
585}
586
587static midipitch_t
588midisyn_clamp_pitch(midipitch_t mp)
589{
590
591	if ( mp <= 0 )
592		return 0;
593	if ( mp >= MIDIPITCH_MAX )
594		return MIDIPITCH_MAX;
595	return mp;
596}
597
598static int16_t
599midisyn_adj_level(midisyn *ms, uint_fast8_t chan)
600{
601	int32_t level;
602
603	KASSERT(mutex_owned(ms->lock));
604
605	level = ms->chnstate[chan].volume + ms->chnstate[chan].expression;
606	if ( level <= INT16_MIN )
607		return INT16_MIN;
608	return level;
609}
610
611static midipitch_t
612midisyn_adj_pitch(midisyn *ms, uint_fast8_t chan)
613{
614	struct channelstate *s = ms->chnstate + chan;
615
616	KASSERT(mutex_owned(ms->lock));
617
618	return s->bend + s->tuning_fine +s->tuning_coarse;
619}
620
621#define VOICECHAN_FOREACH_BEGIN(ms,vp,ch)			\
622	{							\
623		struct voice *vp, *_end_##vp;			\
624		for (vp=(ms)->voices,_end_##vp=vp+(ms)->nvoice;	\
625		    vp < _end_##vp; ++ vp) {			\
626			if ( !vp->inuse )			\
627				continue;			\
628			if ( MS_GETCHAN(vp) == (ch) )		\
629				;				\
630			else					\
631				continue;
632#define VOICECHAN_FOREACH_END }}
633
634static void
635midisyn_chan_releasev(midisyn *ms, uint_fast8_t chan, uint_fast8_t vel)
636{
637
638	KASSERT(mutex_owned(ms->lock));
639
640	VOICECHAN_FOREACH_BEGIN(ms,vp,chan)
641		ms->mets->releasev(ms, vp - ms->voices, vel);
642		midisyn_freevoice(ms, vp - ms->voices);
643	VOICECHAN_FOREACH_END
644}
645
646static void
647midisyn_upd_level(midisyn *ms, uint_fast8_t chan)
648{
649	int32_t level;
650	int16_t chan_level;
651
652	KASSERT(mutex_owned(ms->lock));
653
654	if ( NULL == ms->mets->relevelv )
655		return;
656
657	if ( ms->chnstate[chan].pendingreset & PEND_LEVEL )
658		return;
659
660	chan_level = midisyn_adj_level(ms, chan);
661
662	VOICECHAN_FOREACH_BEGIN(ms,vp,chan)
663		level = vp->velcB + chan_level;
664		ms->mets->relevelv(ms, vp - ms->voices,
665		    level <= INT16_MIN ? INT16_MIN : level);
666	VOICECHAN_FOREACH_END
667}
668
669static void
670midisyn_upd_pitch(midisyn *ms, uint_fast8_t chan)
671{
672	midipitch_t chan_adj;
673
674	KASSERT(mutex_owned(ms->lock));
675
676	if ( NULL == ms->mets->repitchv )
677		return;
678
679	if ( ms->chnstate[chan].pendingreset & PEND_PITCH )
680		return;
681
682	chan_adj = midisyn_adj_pitch(ms, chan);
683
684	VOICECHAN_FOREACH_BEGIN(ms,vp,chan)
685		ms->mets->repitchv(ms, vp - ms->voices,
686		    midisyn_clamp_pitch(chan_adj +
687		        MIDIPITCH_FROM_KEY(vp->chan_note&0x7f)));
688	VOICECHAN_FOREACH_END
689}
690
691#undef VOICECHAN_FOREACH_END
692#undef VOICECHAN_FOREACH_BEGIN
693
694int16_t
695midisyn_vol2cB(uint_fast16_t vol)
696{
697	int16_t cB = 0;
698	int32_t v;
699
700	if ( 0 == vol )
701		return INT16_MIN;
702	/*
703	 * Adjust vol to fall in the range 8192..16383. Each doubling is
704	 * worth 12 dB.
705	 */
706	while ( vol < 8192 ) {
707		vol <<= 1;
708		cB -= 120;
709	}
710	v = vol; /* ensure evaluation in signed 32 bit below */
711	/*
712	 * The GM vol-to-dB formula is dB = 40 log ( v / 127 ) for 7-bit v.
713	 * The vol and expression controllers are in 14-bit space so the
714	 * equivalent is 40 log ( v / 16256 ) - that is, MSB 127 LSB 0 because
715	 * the LSB is commonly unused. MSB 127 LSB 127 would then be a tiny
716	 * bit over.
717	 * 1 dB resolution is a little coarser than we'd like, so let's shoot
718	 * for centibels, i.e. 400 log ( v / 16256 ), and shift everything left
719	 * as far as will fit in 32 bits, which turns out to be a shift of 22.
720	 * This minimax polynomial approximation is good to about a centibel
721	 * on the range 8192..16256, a shade worse (1.4 or so) above that.
722	 * 26385/10166 is the 6th convergent of the coefficient for v^2.
723	 */
724	cB += ( v * ( 124828 - ( v * 26385 ) / 10166 ) - 1347349038 ) >> 22;
725	return cB;
726}
727
728/*
729 * MIDI RP-012 constitutes a MIDI Tuning Specification. The units are
730 * fractional-MIDIkeys, that is, the key number 00 - 7f left shifted
731 * 14 bits to provide a 14-bit fraction that divides each semitone. The
732 * whole thing is just a 21-bit number that is bent and tuned simply by
733 * adding and subtracting--the same offset is the same pitch change anywhere
734 * on the scale. One downside is that a cent is 163.84 of these units, so
735 * you can't expect a lengthy integer sum of cents to come out in tune; if you
736 * do anything in cents it is best to use them only for local adjustment of
737 * a pitch.
738 *
739 * This function converts a pitch in MIDItune units to Hz left-shifted 18 bits.
740 * That should leave you enough to shift down to whatever precision the hardware
741 * supports.
742 *
743 * Its prototype is exposed in <sys/midiio.h>.
744 */
745midihz18_t
746midisyn_mp2hz18(midipitch_t mp)
747{
748	int64_t t64a, t64b;
749	uint_fast8_t shift;
750
751	/*
752	 * Scale from the logarithmic MIDI-Tuning units to Hz<<18. Uses the
753	 * continued-fraction form of a 2/2 rational function derived to
754	 * cover the highest octave (mt 1900544..2097151 or 74.00.00..7f.7f.7f
755	 * in RP-012-speak, the dotted bits are 7 wide) to produce Hz shifted
756	 * left just as far as the maximum Hz will fit in a uint32, which
757	 * turns out to be 18. Just shift off the result for lower octaves.
758	 * Fit is within 1/4 MIDI tuning unit throughout (disclaimer: the
759	 * comparison relied on the double-precision log in libm).
760	 */
761
762	if ( 0 == mp )
763		return 2143236;
764
765	for ( shift = 0; mp < 1900544; ++ shift )
766		mp += MIDIPITCH_OCTAVE;
767
768	if ( 1998848 == mp )
769		return UINT32_C(2463438621) >> shift;
770
771	t64a  = 0x5a1a0ee4; /* INT64_C(967879298788) gcc333: spurious warning */
772	t64a |= (int64_t)0xe1 << 32;
773	t64a /= mp - 1998848; /* here's why 1998848 is special-cased above ;) */
774	t64a += mp - 3704981;
775	t64b  = 0x6763759d; /* INT64_C(8405905567872413) goofy warning again */
776	t64b |= (int64_t)0x1ddd20 << 32;
777	t64b /= t64a;
778	t64b += UINT32_C(2463438619);
779	return (uint32_t)t64b >> shift;
780}
781