xref: /freebsd/sys/dev/sound/pcm/feeder_rate.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * feeder_rate: (Codename: Z Resampler), which means any effort to create
31  *              future replacement for this resampler are simply absurd unless
32  *              the world decide to add new alphabet after Z.
33  *
34  * FreeBSD bandlimited sinc interpolator, technically based on
35  * "Digital Audio Resampling" by Julius O. Smith III
36  *  - http://ccrma.stanford.edu/~jos/resample/
37  *
38  * The Good:
39  * + all out fixed point integer operations, no soft-float or anything like
40  *   that.
41  * + classic polyphase converters with high quality coefficient's polynomial
42  *   interpolators.
43  * + fast, faster, or the fastest of its kind.
44  * + compile time configurable.
45  * + etc etc..
46  *
47  * The Bad:
48  * - The z, z_, and Z_ . Due to mental block (or maybe just 0x7a69), I
49  *   couldn't think of anything simpler than that (feeder_rate_xxx is just
50  *   too long). Expect possible clashes with other zitizens (any?).
51  */
52 
53 #ifdef _KERNEL
54 #ifdef HAVE_KERNEL_OPTION_HEADERS
55 #include "opt_snd.h"
56 #endif
57 #include <dev/sound/pcm/sound.h>
58 #include <dev/sound/pcm/pcm.h>
59 #include "feeder_if.h"
60 
61 #define SND_USE_FXDIV
62 #include "snd_fxdiv_gen.h"
63 #endif
64 
65 #include "feeder_rate_gen.h"
66 
67 #if !defined(_KERNEL) && defined(SND_DIAGNOSTIC)
68 #undef Z_DIAGNOSTIC
69 #define Z_DIAGNOSTIC		1
70 #elif defined(_KERNEL)
71 #undef Z_DIAGNOSTIC
72 #endif
73 
74 #ifndef Z_QUALITY_DEFAULT
75 #define Z_QUALITY_DEFAULT	Z_QUALITY_LINEAR
76 #endif
77 
78 #define Z_RESERVOIR		2048
79 #define Z_RESERVOIR_MAX		131072
80 
81 #define Z_SINC_MAX		0x3fffff
82 #define Z_SINC_DOWNMAX		48		/* 384000 / 8000 */
83 
84 #ifdef _KERNEL
85 #define Z_POLYPHASE_MAX		183040		/* 286 taps, 640 phases */
86 #else
87 #define Z_POLYPHASE_MAX		1464320		/* 286 taps, 5120 phases */
88 #endif
89 
90 #define Z_RATE_DEFAULT		48000
91 
92 #define Z_RATE_MIN		FEEDRATE_RATEMIN
93 #define Z_RATE_MAX		FEEDRATE_RATEMAX
94 #define Z_ROUNDHZ		FEEDRATE_ROUNDHZ
95 #define Z_ROUNDHZ_MIN		FEEDRATE_ROUNDHZ_MIN
96 #define Z_ROUNDHZ_MAX		FEEDRATE_ROUNDHZ_MAX
97 
98 #define Z_RATE_SRC		FEEDRATE_SRC
99 #define Z_RATE_DST		FEEDRATE_DST
100 #define Z_RATE_QUALITY		FEEDRATE_QUALITY
101 #define Z_RATE_CHANNELS		FEEDRATE_CHANNELS
102 
103 #define Z_PARANOID		1
104 
105 #define Z_MULTIFORMAT		1
106 
107 #ifdef _KERNEL
108 #undef Z_USE_ALPHADRIFT
109 #define Z_USE_ALPHADRIFT	1
110 #endif
111 
112 #define Z_FACTOR_MIN		1
113 #define Z_FACTOR_MAX		Z_MASK
114 #define Z_FACTOR_SAFE(v)	(!((v) < Z_FACTOR_MIN || (v) > Z_FACTOR_MAX))
115 
116 struct z_info;
117 
118 typedef void (*z_resampler_t)(struct z_info *, uint8_t *);
119 
120 struct z_info {
121 	int32_t rsrc, rdst;	/* original source / destination rates */
122 	int32_t src, dst;	/* rounded source / destination rates */
123 	int32_t channels;	/* total channels */
124 	int32_t bps;		/* bytes-per-sample */
125 	int32_t quality;	/* resampling quality */
126 
127 	int32_t z_gx, z_gy;	/* interpolation / decimation ratio */
128 	int32_t z_alpha;	/* output sample time phase / drift */
129 	uint8_t *z_delay;	/* FIR delay line / linear buffer */
130 	int32_t *z_coeff;	/* FIR coefficients */
131 	int32_t *z_dcoeff;	/* FIR coefficients differences */
132 	int32_t *z_pcoeff;	/* FIR polyphase coefficients */
133 	int32_t z_scale;	/* output scaling */
134 	int32_t z_dx;		/* input sample drift increment */
135 	int32_t z_dy;		/* output sample drift increment */
136 #ifdef Z_USE_ALPHADRIFT
137 	int32_t z_alphadrift;	/* alpha drift rate */
138 	int32_t z_startdrift;	/* buffer start position drift rate */
139 #endif
140 	int32_t z_mask;		/* delay line full length mask */
141 	int32_t z_size;		/* half width of FIR taps */
142 	int32_t z_full;		/* full size of delay line */
143 	int32_t z_alloc;	/* largest allocated full size of delay line */
144 	int32_t z_start;	/* buffer processing start position */
145 	int32_t z_pos;		/* current position for the next feed */
146 #ifdef Z_DIAGNOSTIC
147 	uint32_t z_cycle;	/* output cycle, purely for statistical */
148 #endif
149 	int32_t z_maxfeed;	/* maximum feed to avoid 32bit overflow */
150 
151 	z_resampler_t z_resample;
152 };
153 
154 int feeder_rate_min = Z_RATE_MIN;
155 int feeder_rate_max = Z_RATE_MAX;
156 int feeder_rate_round = Z_ROUNDHZ;
157 int feeder_rate_quality = Z_QUALITY_DEFAULT;
158 
159 static int feeder_rate_polyphase_max = Z_POLYPHASE_MAX;
160 
161 #ifdef _KERNEL
162 static char feeder_rate_presets[] = FEEDER_RATE_PRESETS;
163 SYSCTL_STRING(_hw_snd, OID_AUTO, feeder_rate_presets, CTLFLAG_RD,
164     &feeder_rate_presets, 0, "compile-time rate presets");
165 SYSCTL_INT(_hw_snd, OID_AUTO, feeder_rate_polyphase_max, CTLFLAG_RWTUN,
166     &feeder_rate_polyphase_max, 0, "maximum allowable polyphase entries");
167 
168 static int
169 sysctl_hw_snd_feeder_rate_min(SYSCTL_HANDLER_ARGS)
170 {
171 	int err, val;
172 
173 	val = feeder_rate_min;
174 	err = sysctl_handle_int(oidp, &val, 0, req);
175 
176 	if (err != 0 || req->newptr == NULL || val == feeder_rate_min)
177 		return (err);
178 
179 	if (!(Z_FACTOR_SAFE(val) && val < feeder_rate_max))
180 		return (EINVAL);
181 
182 	feeder_rate_min = val;
183 
184 	return (0);
185 }
186 SYSCTL_PROC(_hw_snd, OID_AUTO, feeder_rate_min,
187     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
188     sysctl_hw_snd_feeder_rate_min, "I",
189     "minimum allowable rate");
190 
191 static int
192 sysctl_hw_snd_feeder_rate_max(SYSCTL_HANDLER_ARGS)
193 {
194 	int err, val;
195 
196 	val = feeder_rate_max;
197 	err = sysctl_handle_int(oidp, &val, 0, req);
198 
199 	if (err != 0 || req->newptr == NULL || val == feeder_rate_max)
200 		return (err);
201 
202 	if (!(Z_FACTOR_SAFE(val) && val > feeder_rate_min))
203 		return (EINVAL);
204 
205 	feeder_rate_max = val;
206 
207 	return (0);
208 }
209 SYSCTL_PROC(_hw_snd, OID_AUTO, feeder_rate_max,
210     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
211     sysctl_hw_snd_feeder_rate_max, "I",
212     "maximum allowable rate");
213 
214 static int
215 sysctl_hw_snd_feeder_rate_round(SYSCTL_HANDLER_ARGS)
216 {
217 	int err, val;
218 
219 	val = feeder_rate_round;
220 	err = sysctl_handle_int(oidp, &val, 0, req);
221 
222 	if (err != 0 || req->newptr == NULL || val == feeder_rate_round)
223 		return (err);
224 
225 	if (val < Z_ROUNDHZ_MIN || val > Z_ROUNDHZ_MAX)
226 		return (EINVAL);
227 
228 	feeder_rate_round = val - (val % Z_ROUNDHZ);
229 
230 	return (0);
231 }
232 SYSCTL_PROC(_hw_snd, OID_AUTO, feeder_rate_round,
233     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
234     sysctl_hw_snd_feeder_rate_round, "I",
235     "sample rate converter rounding threshold");
236 
237 static int
238 sysctl_hw_snd_feeder_rate_quality(SYSCTL_HANDLER_ARGS)
239 {
240 	struct snddev_info *d;
241 	struct pcm_channel *c;
242 	struct pcm_feeder *f;
243 	int i, err, val;
244 
245 	val = feeder_rate_quality;
246 	err = sysctl_handle_int(oidp, &val, 0, req);
247 
248 	if (err != 0 || req->newptr == NULL || val == feeder_rate_quality)
249 		return (err);
250 
251 	if (val < Z_QUALITY_MIN || val > Z_QUALITY_MAX)
252 		return (EINVAL);
253 
254 	feeder_rate_quality = val;
255 
256 	/*
257 	 * Traverse all available channels on each device and try to
258 	 * set resampler quality if and only if it is exist as
259 	 * part of feeder chains and the channel is idle.
260 	 */
261 	for (i = 0; pcm_devclass != NULL &&
262 	    i < devclass_get_maxunit(pcm_devclass); i++) {
263 		d = devclass_get_softc(pcm_devclass, i);
264 		if (!PCM_REGISTERED(d))
265 			continue;
266 		PCM_LOCK(d);
267 		PCM_WAIT(d);
268 		PCM_ACQUIRE(d);
269 		CHN_FOREACH(c, d, channels.pcm) {
270 			CHN_LOCK(c);
271 			f = feeder_find(c, FEEDER_RATE);
272 			if (f == NULL || f->data == NULL || CHN_STARTED(c)) {
273 				CHN_UNLOCK(c);
274 				continue;
275 			}
276 			(void)FEEDER_SET(f, FEEDRATE_QUALITY, val);
277 			CHN_UNLOCK(c);
278 		}
279 		PCM_RELEASE(d);
280 		PCM_UNLOCK(d);
281 	}
282 
283 	return (0);
284 }
285 SYSCTL_PROC(_hw_snd, OID_AUTO, feeder_rate_quality,
286     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int),
287     sysctl_hw_snd_feeder_rate_quality, "I",
288     "sample rate converter quality ("__XSTRING(Z_QUALITY_MIN)"=low .. "
289     __XSTRING(Z_QUALITY_MAX)"=high)");
290 #endif	/* _KERNEL */
291 
292 /*
293  * Resampler type.
294  */
295 #define Z_IS_ZOH(i)		((i)->quality == Z_QUALITY_ZOH)
296 #define Z_IS_LINEAR(i)		((i)->quality == Z_QUALITY_LINEAR)
297 #define Z_IS_SINC(i)		((i)->quality > Z_QUALITY_LINEAR)
298 
299 /*
300  * Macroses for accurate sample time drift calculations.
301  *
302  * gy2gx : given the amount of output, return the _exact_ required amount of
303  *         input.
304  * gx2gy : given the amount of input, return the _maximum_ amount of output
305  *         that will be generated.
306  * drift : given the amount of input and output, return the elapsed
307  *         sample-time.
308  */
309 #define _Z_GCAST(x)		((uint64_t)(x))
310 
311 #if defined(__i386__)
312 /*
313  * This is where i386 being beaten to a pulp. Fortunately this function is
314  * rarely being called and if it is, it will decide the best (hopefully)
315  * fastest way to do the division. If we can ensure that everything is dword
316  * aligned, letting the compiler to call udivdi3 to do the division can be
317  * faster compared to this.
318  *
319  * amd64 is the clear winner here, no question about it.
320  */
321 static __inline uint32_t
322 Z_DIV(uint64_t v, uint32_t d)
323 {
324 	uint32_t hi, lo, quo, rem;
325 
326 	hi = v >> 32;
327 	lo = v & 0xffffffff;
328 
329 	/*
330 	 * As much as we can, try to avoid long division like a plague.
331 	 */
332 	if (hi == 0)
333 		quo = lo / d;
334 	else
335 		__asm("divl %2"
336 		    : "=a" (quo), "=d" (rem)
337 		    : "r" (d), "0" (lo), "1" (hi));
338 
339 	return (quo);
340 }
341 #else
342 #define Z_DIV(x, y)		((x) / (y))
343 #endif
344 
345 #define _Z_GY2GX(i, a, v)						\
346 	Z_DIV(((_Z_GCAST((i)->z_gx) * (v)) + ((i)->z_gy - (a) - 1)),	\
347 	(i)->z_gy)
348 
349 #define _Z_GX2GY(i, a, v)						\
350 	Z_DIV(((_Z_GCAST((i)->z_gy) * (v)) + (a)), (i)->z_gx)
351 
352 #define _Z_DRIFT(i, x, y)						\
353 	((_Z_GCAST((i)->z_gy) * (x)) - (_Z_GCAST((i)->z_gx) * (y)))
354 
355 #define z_gy2gx(i, v)		_Z_GY2GX(i, (i)->z_alpha, v)
356 #define z_gx2gy(i, v)		_Z_GX2GY(i, (i)->z_alpha, v)
357 #define z_drift(i, x, y)	_Z_DRIFT(i, x, y)
358 
359 /*
360  * Macroses for SINC coefficients table manipulations.. whatever.
361  */
362 #define Z_SINC_COEFF_IDX(i)	((i)->quality - Z_QUALITY_LINEAR - 1)
363 
364 #define Z_SINC_LEN(i)							\
365 	((int32_t)(((uint64_t)z_coeff_tab[Z_SINC_COEFF_IDX(i)].len <<	\
366 	    Z_SHIFT) / (i)->z_dy))
367 
368 #define Z_SINC_BASE_LEN(i)						\
369 	((z_coeff_tab[Z_SINC_COEFF_IDX(i)].len - 1) >> (Z_DRIFT_SHIFT - 1))
370 
371 /*
372  * Macroses for linear delay buffer operations. Alignment is not
373  * really necessary since we're not using true circular buffer, but it
374  * will help us guard against possible trespasser. To be honest,
375  * the linear block operations does not need guarding at all due to
376  * accurate drifting!
377  */
378 #define z_align(i, v)		((v) & (i)->z_mask)
379 #define z_next(i, o, v)		z_align(i, (o) + (v))
380 #define z_prev(i, o, v)		z_align(i, (o) - (v))
381 #define z_fetched(i)		(z_align(i, (i)->z_pos - (i)->z_start) - 1)
382 #define z_free(i)		((i)->z_full - (i)->z_pos)
383 
384 /*
385  * Macroses for Bla Bla .. :)
386  */
387 #define z_copy(src, dst, sz)	(void)memcpy(dst, src, sz)
388 #define z_feed(...)		FEEDER_FEED(__VA_ARGS__)
389 
390 static __inline uint32_t
391 z_min(uint32_t x, uint32_t y)
392 {
393 
394 	return ((x < y) ? x : y);
395 }
396 
397 static int32_t
398 z_gcd(int32_t x, int32_t y)
399 {
400 	int32_t w;
401 
402 	while (y != 0) {
403 		w = x % y;
404 		x = y;
405 		y = w;
406 	}
407 
408 	return (x);
409 }
410 
411 static int32_t
412 z_roundpow2(int32_t v)
413 {
414 	int32_t i;
415 
416 	i = 1;
417 
418 	/*
419 	 * Let it overflow at will..
420 	 */
421 	while (i > 0 && i < v)
422 		i <<= 1;
423 
424 	return (i);
425 }
426 
427 /*
428  * Zero Order Hold, the worst of the worst, an insult against quality,
429  * but super fast.
430  */
431 static void
432 z_feed_zoh(struct z_info *info, uint8_t *dst)
433 {
434 	uint32_t cnt;
435 	uint8_t *src;
436 
437 	cnt = info->channels * info->bps;
438 	src = info->z_delay + (info->z_start * cnt);
439 
440 	/*
441 	 * This is a bit faster than doing bcopy() since we're dealing
442 	 * with possible unaligned samples.
443 	 */
444 	do {
445 		*dst++ = *src++;
446 	} while (--cnt != 0);
447 }
448 
449 /*
450  * Linear Interpolation. This at least sounds better (perceptually) and fast,
451  * but without any proper filtering which means aliasing still exist and
452  * could become worst with a right sample. Interpolation centered within
453  * Z_LINEAR_ONE between the present and previous sample and everything is
454  * done with simple 32bit scaling arithmetic.
455  */
456 #define Z_DECLARE_LINEAR(SIGN, BIT, ENDIAN)					\
457 static void									\
458 z_feed_linear_##SIGN##BIT##ENDIAN(struct z_info *info, uint8_t *dst)		\
459 {										\
460 	int32_t z;								\
461 	intpcm_t x, y;								\
462 	uint32_t ch;								\
463 	uint8_t *sx, *sy;							\
464 										\
465 	z = ((uint32_t)info->z_alpha * info->z_dx) >> Z_LINEAR_UNSHIFT;		\
466 										\
467 	sx = info->z_delay + (info->z_start * info->channels *			\
468 	    PCM_##BIT##_BPS);							\
469 	sy = sx - (info->channels * PCM_##BIT##_BPS);				\
470 										\
471 	ch = info->channels;							\
472 										\
473 	do {									\
474 		x = _PCM_READ_##SIGN##BIT##_##ENDIAN(sx);			\
475 		y = _PCM_READ_##SIGN##BIT##_##ENDIAN(sy);			\
476 		x = Z_LINEAR_INTERPOLATE_##BIT(z, x, y);			\
477 		_PCM_WRITE_##SIGN##BIT##_##ENDIAN(dst, x);			\
478 		sx += PCM_##BIT##_BPS;						\
479 		sy += PCM_##BIT##_BPS;						\
480 		dst += PCM_##BIT##_BPS;						\
481 	} while (--ch != 0);							\
482 }
483 
484 /*
485  * Userland clipping diagnostic check, not enabled in kernel compilation.
486  * While doing sinc interpolation, unrealistic samples like full scale sine
487  * wav will clip, but for other things this will not make any noise at all.
488  * Everybody should learn how to normalized perceived loudness of their own
489  * music/sounds/samples (hint: ReplayGain).
490  */
491 #ifdef Z_DIAGNOSTIC
492 #define Z_CLIP_CHECK(v, BIT)	do {					\
493 	if ((v) > PCM_S##BIT##_MAX) {					\
494 		fprintf(stderr, "Overflow: v=%jd, max=%jd\n",		\
495 		    (intmax_t)(v), (intmax_t)PCM_S##BIT##_MAX);		\
496 	} else if ((v) < PCM_S##BIT##_MIN) {				\
497 		fprintf(stderr, "Underflow: v=%jd, min=%jd\n",		\
498 		    (intmax_t)(v), (intmax_t)PCM_S##BIT##_MIN);		\
499 	}								\
500 } while (0)
501 #else
502 #define Z_CLIP_CHECK(...)
503 #endif
504 
505 #define Z_CLAMP(v, BIT)							\
506 	(((v) > PCM_S##BIT##_MAX) ? PCM_S##BIT##_MAX :			\
507 	(((v) < PCM_S##BIT##_MIN) ? PCM_S##BIT##_MIN : (v)))
508 
509 /*
510  * Sine Cardinal (SINC) Interpolation. Scaling is done in 64 bit, so
511  * there's no point to hold the plate any longer. All samples will be
512  * shifted to a full 32 bit, scaled and restored during write for
513  * maximum dynamic range (only for downsampling).
514  */
515 #define _Z_SINC_ACCUMULATE(SIGN, BIT, ENDIAN, adv)			\
516 	c += z >> Z_SHIFT;						\
517 	z &= Z_MASK;							\
518 	coeff = Z_COEFF_INTERPOLATE(z, z_coeff[c], z_dcoeff[c]);	\
519 	x = _PCM_READ_##SIGN##BIT##_##ENDIAN(p);			\
520 	v += Z_NORM_##BIT((intpcm64_t)x * coeff);			\
521 	z += info->z_dy;						\
522 	p adv##= info->channels * PCM_##BIT##_BPS
523 
524 /*
525  * XXX GCC4 optimization is such a !@#$%, need manual unrolling.
526  */
527 #if defined(__GNUC__) && __GNUC__ >= 4
528 #define Z_SINC_ACCUMULATE(...)	do {					\
529 	_Z_SINC_ACCUMULATE(__VA_ARGS__);				\
530 	_Z_SINC_ACCUMULATE(__VA_ARGS__);				\
531 } while (0)
532 #define Z_SINC_ACCUMULATE_DECR		2
533 #else
534 #define Z_SINC_ACCUMULATE(...)	do {					\
535 	_Z_SINC_ACCUMULATE(__VA_ARGS__);				\
536 } while (0)
537 #define Z_SINC_ACCUMULATE_DECR		1
538 #endif
539 
540 #define Z_DECLARE_SINC(SIGN, BIT, ENDIAN)					\
541 static void									\
542 z_feed_sinc_##SIGN##BIT##ENDIAN(struct z_info *info, uint8_t *dst)		\
543 {										\
544 	intpcm64_t v;								\
545 	intpcm_t x;								\
546 	uint8_t *p;								\
547 	int32_t coeff, z, *z_coeff, *z_dcoeff;					\
548 	uint32_t c, center, ch, i;						\
549 										\
550 	z_coeff = info->z_coeff;						\
551 	z_dcoeff = info->z_dcoeff;						\
552 	center = z_prev(info, info->z_start, info->z_size);			\
553 	ch = info->channels * PCM_##BIT##_BPS;					\
554 	dst += ch;								\
555 										\
556 	do {									\
557 		dst -= PCM_##BIT##_BPS;						\
558 		ch -= PCM_##BIT##_BPS;						\
559 		v = 0;								\
560 		z = info->z_alpha * info->z_dx;					\
561 		c = 0;								\
562 		p = info->z_delay + (z_next(info, center, 1) *			\
563 		    info->channels * PCM_##BIT##_BPS) + ch;			\
564 		for (i = info->z_size; i != 0; i -= Z_SINC_ACCUMULATE_DECR) 	\
565 			Z_SINC_ACCUMULATE(SIGN, BIT, ENDIAN, +);		\
566 		z = info->z_dy - (info->z_alpha * info->z_dx);			\
567 		c = 0;								\
568 		p = info->z_delay + (center * info->channels *			\
569 		    PCM_##BIT##_BPS) + ch;					\
570 		for (i = info->z_size; i != 0; i -= Z_SINC_ACCUMULATE_DECR) 	\
571 			Z_SINC_ACCUMULATE(SIGN, BIT, ENDIAN, -);		\
572 		if (info->z_scale != Z_ONE)					\
573 			v = Z_SCALE_##BIT(v, info->z_scale);			\
574 		else								\
575 			v >>= Z_COEFF_SHIFT - Z_GUARD_BIT_##BIT;		\
576 		Z_CLIP_CHECK(v, BIT);						\
577 		_PCM_WRITE_##SIGN##BIT##_##ENDIAN(dst, Z_CLAMP(v, BIT));	\
578 	} while (ch != 0);							\
579 }
580 
581 #define Z_DECLARE_SINC_POLYPHASE(SIGN, BIT, ENDIAN)				\
582 static void									\
583 z_feed_sinc_polyphase_##SIGN##BIT##ENDIAN(struct z_info *info, uint8_t *dst)	\
584 {										\
585 	intpcm64_t v;								\
586 	intpcm_t x;								\
587 	uint8_t *p;								\
588 	int32_t ch, i, start, *z_pcoeff;					\
589 										\
590 	ch = info->channels * PCM_##BIT##_BPS;					\
591 	dst += ch;								\
592 	start = z_prev(info, info->z_start, (info->z_size << 1) - 1) * ch;	\
593 										\
594 	do {									\
595 		dst -= PCM_##BIT##_BPS;						\
596 		ch -= PCM_##BIT##_BPS;						\
597 		v = 0;								\
598 		p = info->z_delay + start + ch;					\
599 		z_pcoeff = info->z_pcoeff +					\
600 		    ((info->z_alpha * info->z_size) << 1);			\
601 		for (i = info->z_size; i != 0; i--) {				\
602 			x = _PCM_READ_##SIGN##BIT##_##ENDIAN(p);		\
603 			v += Z_NORM_##BIT((intpcm64_t)x * *z_pcoeff);		\
604 			z_pcoeff++;						\
605 			p += info->channels * PCM_##BIT##_BPS;			\
606 			x = _PCM_READ_##SIGN##BIT##_##ENDIAN(p);		\
607 			v += Z_NORM_##BIT((intpcm64_t)x * *z_pcoeff);		\
608 			z_pcoeff++;						\
609 			p += info->channels * PCM_##BIT##_BPS;			\
610 		}								\
611 		if (info->z_scale != Z_ONE)					\
612 			v = Z_SCALE_##BIT(v, info->z_scale);			\
613 		else								\
614 			v >>= Z_COEFF_SHIFT - Z_GUARD_BIT_##BIT;		\
615 		Z_CLIP_CHECK(v, BIT);						\
616 		_PCM_WRITE_##SIGN##BIT##_##ENDIAN(dst, Z_CLAMP(v, BIT));	\
617 	} while (ch != 0);							\
618 }
619 
620 #define Z_DECLARE(SIGN, BIT, ENDIAN)					\
621 	Z_DECLARE_LINEAR(SIGN, BIT, ENDIAN)				\
622 	Z_DECLARE_SINC(SIGN, BIT, ENDIAN)				\
623 	Z_DECLARE_SINC_POLYPHASE(SIGN, BIT, ENDIAN)
624 
625 #if BYTE_ORDER == LITTLE_ENDIAN || defined(SND_FEEDER_MULTIFORMAT)
626 Z_DECLARE(S, 16, LE)
627 Z_DECLARE(S, 32, LE)
628 #endif
629 #if BYTE_ORDER == BIG_ENDIAN || defined(SND_FEEDER_MULTIFORMAT)
630 Z_DECLARE(S, 16, BE)
631 Z_DECLARE(S, 32, BE)
632 #endif
633 #ifdef SND_FEEDER_MULTIFORMAT
634 Z_DECLARE(S,  8, NE)
635 Z_DECLARE(S, 24, LE)
636 Z_DECLARE(S, 24, BE)
637 Z_DECLARE(U,  8, NE)
638 Z_DECLARE(U, 16, LE)
639 Z_DECLARE(U, 24, LE)
640 Z_DECLARE(U, 32, LE)
641 Z_DECLARE(U, 16, BE)
642 Z_DECLARE(U, 24, BE)
643 Z_DECLARE(U, 32, BE)
644 #endif
645 
646 enum {
647 	Z_RESAMPLER_ZOH,
648 	Z_RESAMPLER_LINEAR,
649 	Z_RESAMPLER_SINC,
650 	Z_RESAMPLER_SINC_POLYPHASE,
651 	Z_RESAMPLER_LAST
652 };
653 
654 #define Z_RESAMPLER_IDX(i)						\
655 	(Z_IS_SINC(i) ? Z_RESAMPLER_SINC : (i)->quality)
656 
657 #define Z_RESAMPLER_ENTRY(SIGN, BIT, ENDIAN)					\
658 	{									\
659 	    AFMT_##SIGN##BIT##_##ENDIAN,					\
660 	    {									\
661 		[Z_RESAMPLER_ZOH]    = z_feed_zoh,				\
662 		[Z_RESAMPLER_LINEAR] = z_feed_linear_##SIGN##BIT##ENDIAN,	\
663 		[Z_RESAMPLER_SINC]   = z_feed_sinc_##SIGN##BIT##ENDIAN,		\
664 		[Z_RESAMPLER_SINC_POLYPHASE]   =				\
665 		    z_feed_sinc_polyphase_##SIGN##BIT##ENDIAN			\
666 	    }									\
667 	}
668 
669 static const struct {
670 	uint32_t format;
671 	z_resampler_t resampler[Z_RESAMPLER_LAST];
672 } z_resampler_tab[] = {
673 #if BYTE_ORDER == LITTLE_ENDIAN || defined(SND_FEEDER_MULTIFORMAT)
674 	Z_RESAMPLER_ENTRY(S, 16, LE),
675 	Z_RESAMPLER_ENTRY(S, 32, LE),
676 #endif
677 #if BYTE_ORDER == BIG_ENDIAN || defined(SND_FEEDER_MULTIFORMAT)
678 	Z_RESAMPLER_ENTRY(S, 16, BE),
679 	Z_RESAMPLER_ENTRY(S, 32, BE),
680 #endif
681 #ifdef SND_FEEDER_MULTIFORMAT
682 	Z_RESAMPLER_ENTRY(S,  8, NE),
683 	Z_RESAMPLER_ENTRY(S, 24, LE),
684 	Z_RESAMPLER_ENTRY(S, 24, BE),
685 	Z_RESAMPLER_ENTRY(U,  8, NE),
686 	Z_RESAMPLER_ENTRY(U, 16, LE),
687 	Z_RESAMPLER_ENTRY(U, 24, LE),
688 	Z_RESAMPLER_ENTRY(U, 32, LE),
689 	Z_RESAMPLER_ENTRY(U, 16, BE),
690 	Z_RESAMPLER_ENTRY(U, 24, BE),
691 	Z_RESAMPLER_ENTRY(U, 32, BE),
692 #endif
693 };
694 
695 #define Z_RESAMPLER_TAB_SIZE						\
696 	((int32_t)(sizeof(z_resampler_tab) / sizeof(z_resampler_tab[0])))
697 
698 static void
699 z_resampler_reset(struct z_info *info)
700 {
701 
702 	info->src = info->rsrc - (info->rsrc % ((feeder_rate_round > 0 &&
703 	    info->rsrc > feeder_rate_round) ? feeder_rate_round : 1));
704 	info->dst = info->rdst - (info->rdst % ((feeder_rate_round > 0 &&
705 	    info->rdst > feeder_rate_round) ? feeder_rate_round : 1));
706 	info->z_gx = 1;
707 	info->z_gy = 1;
708 	info->z_alpha = 0;
709 	info->z_resample = NULL;
710 	info->z_size = 1;
711 	info->z_coeff = NULL;
712 	info->z_dcoeff = NULL;
713 	if (info->z_pcoeff != NULL) {
714 		free(info->z_pcoeff, M_DEVBUF);
715 		info->z_pcoeff = NULL;
716 	}
717 	info->z_scale = Z_ONE;
718 	info->z_dx = Z_FULL_ONE;
719 	info->z_dy = Z_FULL_ONE;
720 #ifdef Z_DIAGNOSTIC
721 	info->z_cycle = 0;
722 #endif
723 	if (info->quality < Z_QUALITY_MIN)
724 		info->quality = Z_QUALITY_MIN;
725 	else if (info->quality > Z_QUALITY_MAX)
726 		info->quality = Z_QUALITY_MAX;
727 }
728 
729 #ifdef Z_PARANOID
730 static int32_t
731 z_resampler_sinc_len(struct z_info *info)
732 {
733 	int32_t c, z, len, lmax;
734 
735 	if (!Z_IS_SINC(info))
736 		return (1);
737 
738 	/*
739 	 * A rather careful (or useless) way to calculate filter length.
740 	 * Z_SINC_LEN() itself is accurate enough to do its job. Extra
741 	 * sanity checking is not going to hurt though..
742 	 */
743 	c = 0;
744 	z = info->z_dy;
745 	len = 0;
746 	lmax = z_coeff_tab[Z_SINC_COEFF_IDX(info)].len;
747 
748 	do {
749 		c += z >> Z_SHIFT;
750 		z &= Z_MASK;
751 		z += info->z_dy;
752 	} while (c < lmax && ++len > 0);
753 
754 	if (len != Z_SINC_LEN(info)) {
755 #ifdef _KERNEL
756 		printf("%s(): sinc l=%d != Z_SINC_LEN=%d\n",
757 		    __func__, len, Z_SINC_LEN(info));
758 #else
759 		fprintf(stderr, "%s(): sinc l=%d != Z_SINC_LEN=%d\n",
760 		    __func__, len, Z_SINC_LEN(info));
761 		return (-1);
762 #endif
763 	}
764 
765 	return (len);
766 }
767 #else
768 #define z_resampler_sinc_len(i)		(Z_IS_SINC(i) ? Z_SINC_LEN(i) : 1)
769 #endif
770 
771 #define Z_POLYPHASE_COEFF_SHIFT		0
772 
773 /*
774  * Pick suitable polynomial interpolators based on filter oversampled ratio
775  * (2 ^ Z_DRIFT_SHIFT).
776  */
777 #if !(defined(Z_COEFF_INTERP_ZOH) || defined(Z_COEFF_INTERP_LINEAR) ||		\
778     defined(Z_COEFF_INTERP_QUADRATIC) || defined(Z_COEFF_INTERP_HERMITE) ||	\
779     defined(Z_COEFF_INTER_BSPLINE) || defined(Z_COEFF_INTERP_OPT32X) ||		\
780     defined(Z_COEFF_INTERP_OPT16X) || defined(Z_COEFF_INTERP_OPT8X) ||		\
781     defined(Z_COEFF_INTERP_OPT4X) || defined(Z_COEFF_INTERP_OPT2X))
782 #if Z_DRIFT_SHIFT >= 6
783 #define Z_COEFF_INTERP_BSPLINE		1
784 #elif Z_DRIFT_SHIFT >= 5
785 #define Z_COEFF_INTERP_OPT32X		1
786 #elif Z_DRIFT_SHIFT == 4
787 #define Z_COEFF_INTERP_OPT16X		1
788 #elif Z_DRIFT_SHIFT == 3
789 #define Z_COEFF_INTERP_OPT8X		1
790 #elif Z_DRIFT_SHIFT == 2
791 #define Z_COEFF_INTERP_OPT4X		1
792 #elif Z_DRIFT_SHIFT == 1
793 #define Z_COEFF_INTERP_OPT2X		1
794 #else
795 #error "Z_DRIFT_SHIFT screwed!"
796 #endif
797 #endif
798 
799 /*
800  * In classic polyphase mode, the actual coefficients for each phases need to
801  * be calculated based on default prototype filters. For highly oversampled
802  * filter, linear or quadradatic interpolator should be enough. Anything less
803  * than that require 'special' interpolators to reduce interpolation errors.
804  *
805  * "Polynomial Interpolators for High-Quality Resampling of Oversampled Audio"
806  *    by Olli Niemitalo
807  *    - http://www.student.oulu.fi/~oniemita/dsp/deip.pdf
808  *
809  */
810 static int32_t
811 z_coeff_interpolate(int32_t z, int32_t *z_coeff)
812 {
813 	int32_t coeff;
814 #if defined(Z_COEFF_INTERP_ZOH)
815 
816 	/* 1-point, 0th-order (Zero Order Hold) */
817 	z = z;
818 	coeff = z_coeff[0];
819 #elif defined(Z_COEFF_INTERP_LINEAR)
820 	int32_t zl0, zl1;
821 
822 	/* 2-point, 1st-order Linear */
823 	zl0 = z_coeff[0];
824 	zl1 = z_coeff[1] - z_coeff[0];
825 
826 	coeff = Z_RSHIFT((int64_t)zl1 * z, Z_SHIFT) + zl0;
827 #elif defined(Z_COEFF_INTERP_QUADRATIC)
828 	int32_t zq0, zq1, zq2;
829 
830 	/* 3-point, 2nd-order Quadratic */
831 	zq0 = z_coeff[0];
832 	zq1 = z_coeff[1] - z_coeff[-1];
833 	zq2 = z_coeff[1] + z_coeff[-1] - (z_coeff[0] << 1);
834 
835 	coeff = Z_RSHIFT((Z_RSHIFT((int64_t)zq2 * z, Z_SHIFT) +
836 	    zq1) * z, Z_SHIFT + 1) + zq0;
837 #elif defined(Z_COEFF_INTERP_HERMITE)
838 	int32_t zh0, zh1, zh2, zh3;
839 
840 	/* 4-point, 3rd-order Hermite */
841 	zh0 = z_coeff[0];
842 	zh1 = z_coeff[1] - z_coeff[-1];
843 	zh2 = (z_coeff[-1] << 1) - (z_coeff[0] * 5) + (z_coeff[1] << 2) -
844 	    z_coeff[2];
845 	zh3 = z_coeff[2] - z_coeff[-1] + ((z_coeff[0] - z_coeff[1]) * 3);
846 
847 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((int64_t)zh3 * z, Z_SHIFT) +
848 	    zh2) * z, Z_SHIFT) + zh1) * z, Z_SHIFT + 1) + zh0;
849 #elif defined(Z_COEFF_INTERP_BSPLINE)
850 	int32_t zb0, zb1, zb2, zb3;
851 
852 	/* 4-point, 3rd-order B-Spline */
853 	zb0 = Z_RSHIFT(0x15555555LL * (((int64_t)z_coeff[0] << 2) +
854 	    z_coeff[-1] + z_coeff[1]), 30);
855 	zb1 = z_coeff[1] - z_coeff[-1];
856 	zb2 = z_coeff[-1] + z_coeff[1] - (z_coeff[0] << 1);
857 	zb3 = Z_RSHIFT(0x15555555LL * (((z_coeff[0] - z_coeff[1]) * 3) +
858 	    z_coeff[2] - z_coeff[-1]), 30);
859 
860 	coeff = (Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((int64_t)zb3 * z, Z_SHIFT) +
861 	    zb2) * z, Z_SHIFT) + zb1) * z, Z_SHIFT) + zb0 + 1) >> 1;
862 #elif defined(Z_COEFF_INTERP_OPT32X)
863 	int32_t zoz, zoe1, zoe2, zoe3, zoo1, zoo2, zoo3;
864 	int32_t zoc0, zoc1, zoc2, zoc3, zoc4, zoc5;
865 
866 	/* 6-point, 5th-order Optimal 32x */
867 	zoz = z - (Z_ONE >> 1);
868 	zoe1 = z_coeff[1] + z_coeff[0];
869 	zoe2 = z_coeff[2] + z_coeff[-1];
870 	zoe3 = z_coeff[3] + z_coeff[-2];
871 	zoo1 = z_coeff[1] - z_coeff[0];
872 	zoo2 = z_coeff[2] - z_coeff[-1];
873 	zoo3 = z_coeff[3] - z_coeff[-2];
874 
875 	zoc0 = Z_RSHIFT((0x1ac2260dLL * zoe1) + (0x0526cdcaLL * zoe2) +
876 	    (0x00170c29LL * zoe3), 30);
877 	zoc1 = Z_RSHIFT((0x14f8a49aLL * zoo1) + (0x0d6d1109LL * zoo2) +
878 	    (0x008cd4dcLL * zoo3), 30);
879 	zoc2 = Z_RSHIFT((-0x0d3e94a4LL * zoe1) + (0x0bddded4LL * zoe2) +
880 	    (0x0160b5d0LL * zoe3), 30);
881 	zoc3 = Z_RSHIFT((-0x0de10cc4LL * zoo1) + (0x019b2a7dLL * zoo2) +
882 	    (0x01cfe914LL * zoo3), 30);
883 	zoc4 = Z_RSHIFT((0x02aa12d7LL * zoe1) + (-0x03ff1bb3LL * zoe2) +
884 	    (0x015508ddLL * zoe3), 30);
885 	zoc5 = Z_RSHIFT((0x051d29e5LL * zoo1) + (-0x028e7647LL * zoo2) +
886 	    (0x0082d81aLL * zoo3), 30);
887 
888 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT(
889 	    (int64_t)zoc5 * zoz, Z_SHIFT) +
890 	    zoc4) * zoz, Z_SHIFT) + zoc3) * zoz, Z_SHIFT) +
891 	    zoc2) * zoz, Z_SHIFT) + zoc1) * zoz, Z_SHIFT) + zoc0;
892 #elif defined(Z_COEFF_INTERP_OPT16X)
893 	int32_t zoz, zoe1, zoe2, zoe3, zoo1, zoo2, zoo3;
894 	int32_t zoc0, zoc1, zoc2, zoc3, zoc4, zoc5;
895 
896 	/* 6-point, 5th-order Optimal 16x */
897 	zoz = z - (Z_ONE >> 1);
898 	zoe1 = z_coeff[1] + z_coeff[0];
899 	zoe2 = z_coeff[2] + z_coeff[-1];
900 	zoe3 = z_coeff[3] + z_coeff[-2];
901 	zoo1 = z_coeff[1] - z_coeff[0];
902 	zoo2 = z_coeff[2] - z_coeff[-1];
903 	zoo3 = z_coeff[3] - z_coeff[-2];
904 
905 	zoc0 = Z_RSHIFT((0x1ac2260dLL * zoe1) + (0x0526cdcaLL * zoe2) +
906 	    (0x00170c29LL * zoe3), 30);
907 	zoc1 = Z_RSHIFT((0x14f8a49aLL * zoo1) + (0x0d6d1109LL * zoo2) +
908 	    (0x008cd4dcLL * zoo3), 30);
909 	zoc2 = Z_RSHIFT((-0x0d3e94a4LL * zoe1) + (0x0bddded4LL * zoe2) +
910 	    (0x0160b5d0LL * zoe3), 30);
911 	zoc3 = Z_RSHIFT((-0x0de10cc4LL * zoo1) + (0x019b2a7dLL * zoo2) +
912 	    (0x01cfe914LL * zoo3), 30);
913 	zoc4 = Z_RSHIFT((0x02aa12d7LL * zoe1) + (-0x03ff1bb3LL * zoe2) +
914 	    (0x015508ddLL * zoe3), 30);
915 	zoc5 = Z_RSHIFT((0x051d29e5LL * zoo1) + (-0x028e7647LL * zoo2) +
916 	    (0x0082d81aLL * zoo3), 30);
917 
918 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT(
919 	    (int64_t)zoc5 * zoz, Z_SHIFT) +
920 	    zoc4) * zoz, Z_SHIFT) + zoc3) * zoz, Z_SHIFT) +
921 	    zoc2) * zoz, Z_SHIFT) + zoc1) * zoz, Z_SHIFT) + zoc0;
922 #elif defined(Z_COEFF_INTERP_OPT8X)
923 	int32_t zoz, zoe1, zoe2, zoe3, zoo1, zoo2, zoo3;
924 	int32_t zoc0, zoc1, zoc2, zoc3, zoc4, zoc5;
925 
926 	/* 6-point, 5th-order Optimal 8x */
927 	zoz = z - (Z_ONE >> 1);
928 	zoe1 = z_coeff[1] + z_coeff[0];
929 	zoe2 = z_coeff[2] + z_coeff[-1];
930 	zoe3 = z_coeff[3] + z_coeff[-2];
931 	zoo1 = z_coeff[1] - z_coeff[0];
932 	zoo2 = z_coeff[2] - z_coeff[-1];
933 	zoo3 = z_coeff[3] - z_coeff[-2];
934 
935 	zoc0 = Z_RSHIFT((0x1aa9b47dLL * zoe1) + (0x053d9944LL * zoe2) +
936 	    (0x0018b23fLL * zoe3), 30);
937 	zoc1 = Z_RSHIFT((0x14a104d1LL * zoo1) + (0x0d7d2504LL * zoo2) +
938 	    (0x0094b599LL * zoo3), 30);
939 	zoc2 = Z_RSHIFT((-0x0d22530bLL * zoe1) + (0x0bb37a2cLL * zoe2) +
940 	    (0x016ed8e0LL * zoe3), 30);
941 	zoc3 = Z_RSHIFT((-0x0d744b1cLL * zoo1) + (0x01649591LL * zoo2) +
942 	    (0x01dae93aLL * zoo3), 30);
943 	zoc4 = Z_RSHIFT((0x02a7ee1bLL * zoe1) + (-0x03fbdb24LL * zoe2) +
944 	    (0x0153ed07LL * zoe3), 30);
945 	zoc5 = Z_RSHIFT((0x04cf9b6cLL * zoo1) + (-0x0266b378LL * zoo2) +
946 	    (0x007a7c26LL * zoo3), 30);
947 
948 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT(
949 	    (int64_t)zoc5 * zoz, Z_SHIFT) +
950 	    zoc4) * zoz, Z_SHIFT) + zoc3) * zoz, Z_SHIFT) +
951 	    zoc2) * zoz, Z_SHIFT) + zoc1) * zoz, Z_SHIFT) + zoc0;
952 #elif defined(Z_COEFF_INTERP_OPT4X)
953 	int32_t zoz, zoe1, zoe2, zoe3, zoo1, zoo2, zoo3;
954 	int32_t zoc0, zoc1, zoc2, zoc3, zoc4, zoc5;
955 
956 	/* 6-point, 5th-order Optimal 4x */
957 	zoz = z - (Z_ONE >> 1);
958 	zoe1 = z_coeff[1] + z_coeff[0];
959 	zoe2 = z_coeff[2] + z_coeff[-1];
960 	zoe3 = z_coeff[3] + z_coeff[-2];
961 	zoo1 = z_coeff[1] - z_coeff[0];
962 	zoo2 = z_coeff[2] - z_coeff[-1];
963 	zoo3 = z_coeff[3] - z_coeff[-2];
964 
965 	zoc0 = Z_RSHIFT((0x1a8eda43LL * zoe1) + (0x0556ee38LL * zoe2) +
966 	    (0x001a3784LL * zoe3), 30);
967 	zoc1 = Z_RSHIFT((0x143d863eLL * zoo1) + (0x0d910e36LL * zoo2) +
968 	    (0x009ca889LL * zoo3), 30);
969 	zoc2 = Z_RSHIFT((-0x0d026821LL * zoe1) + (0x0b837773LL * zoe2) +
970 	    (0x017ef0c6LL * zoe3), 30);
971 	zoc3 = Z_RSHIFT((-0x0cef1502LL * zoo1) + (0x01207a8eLL * zoo2) +
972 	    (0x01e936dbLL * zoo3), 30);
973 	zoc4 = Z_RSHIFT((0x029fe643LL * zoe1) + (-0x03ef3fc8LL * zoe2) +
974 	    (0x014f5923LL * zoe3), 30);
975 	zoc5 = Z_RSHIFT((0x043a9d08LL * zoo1) + (-0x02154febLL * zoo2) +
976 	    (0x00670dbdLL * zoo3), 30);
977 
978 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT(
979 	    (int64_t)zoc5 * zoz, Z_SHIFT) +
980 	    zoc4) * zoz, Z_SHIFT) + zoc3) * zoz, Z_SHIFT) +
981 	    zoc2) * zoz, Z_SHIFT) + zoc1) * zoz, Z_SHIFT) + zoc0;
982 #elif defined(Z_COEFF_INTERP_OPT2X)
983 	int32_t zoz, zoe1, zoe2, zoe3, zoo1, zoo2, zoo3;
984 	int32_t zoc0, zoc1, zoc2, zoc3, zoc4, zoc5;
985 
986 	/* 6-point, 5th-order Optimal 2x */
987 	zoz = z - (Z_ONE >> 1);
988 	zoe1 = z_coeff[1] + z_coeff[0];
989 	zoe2 = z_coeff[2] + z_coeff[-1];
990 	zoe3 = z_coeff[3] + z_coeff[-2];
991 	zoo1 = z_coeff[1] - z_coeff[0];
992 	zoo2 = z_coeff[2] - z_coeff[-1];
993 	zoo3 = z_coeff[3] - z_coeff[-2];
994 
995 	zoc0 = Z_RSHIFT((0x19edb6fdLL * zoe1) + (0x05ebd062LL * zoe2) +
996 	    (0x00267881LL * zoe3), 30);
997 	zoc1 = Z_RSHIFT((0x1223af76LL * zoo1) + (0x0de3dd6bLL * zoo2) +
998 	    (0x00d683cdLL * zoo3), 30);
999 	zoc2 = Z_RSHIFT((-0x0c3ee068LL * zoe1) + (0x0a5c3769LL * zoe2) +
1000 	    (0x01e2aceaLL * zoe3), 30);
1001 	zoc3 = Z_RSHIFT((-0x0a8ab614LL * zoo1) + (-0x0019522eLL * zoo2) +
1002 	    (0x022cefc7LL * zoo3), 30);
1003 	zoc4 = Z_RSHIFT((0x0276187dLL * zoe1) + (-0x03a801e8LL * zoe2) +
1004 	    (0x0131d935LL * zoe3), 30);
1005 	zoc5 = Z_RSHIFT((0x02c373f5LL * zoo1) + (-0x01275f83LL * zoo2) +
1006 	    (0x0018ee79LL * zoo3), 30);
1007 
1008 	coeff = Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT((Z_RSHIFT(
1009 	    (int64_t)zoc5 * zoz, Z_SHIFT) +
1010 	    zoc4) * zoz, Z_SHIFT) + zoc3) * zoz, Z_SHIFT) +
1011 	    zoc2) * zoz, Z_SHIFT) + zoc1) * zoz, Z_SHIFT) + zoc0;
1012 #else
1013 #error "Interpolation type screwed!"
1014 #endif
1015 
1016 #if Z_POLYPHASE_COEFF_SHIFT > 0
1017 	coeff = Z_RSHIFT(coeff, Z_POLYPHASE_COEFF_SHIFT);
1018 #endif
1019 	return (coeff);
1020 }
1021 
1022 static int
1023 z_resampler_build_polyphase(struct z_info *info)
1024 {
1025 	int32_t alpha, c, i, z, idx;
1026 
1027 	/* Let this be here first. */
1028 	if (info->z_pcoeff != NULL) {
1029 		free(info->z_pcoeff, M_DEVBUF);
1030 		info->z_pcoeff = NULL;
1031 	}
1032 
1033 	if (feeder_rate_polyphase_max < 1)
1034 		return (ENOTSUP);
1035 
1036 	if (((int64_t)info->z_size * info->z_gy * 2) >
1037 	    feeder_rate_polyphase_max) {
1038 #ifndef _KERNEL
1039 		fprintf(stderr, "Polyphase entries exceed: [%d/%d] %jd > %d\n",
1040 		    info->z_gx, info->z_gy,
1041 		    (intmax_t)info->z_size * info->z_gy * 2,
1042 		    feeder_rate_polyphase_max);
1043 #endif
1044 		return (E2BIG);
1045 	}
1046 
1047 	info->z_pcoeff = malloc(sizeof(int32_t) *
1048 	    info->z_size * info->z_gy * 2, M_DEVBUF, M_NOWAIT | M_ZERO);
1049 	if (info->z_pcoeff == NULL)
1050 		return (ENOMEM);
1051 
1052 	for (alpha = 0; alpha < info->z_gy; alpha++) {
1053 		z = alpha * info->z_dx;
1054 		c = 0;
1055 		for (i = info->z_size; i != 0; i--) {
1056 			c += z >> Z_SHIFT;
1057 			z &= Z_MASK;
1058 			idx = (alpha * info->z_size * 2) +
1059 			    (info->z_size * 2) - i;
1060 			info->z_pcoeff[idx] =
1061 			    z_coeff_interpolate(z, info->z_coeff + c);
1062 			z += info->z_dy;
1063 		}
1064 		z = info->z_dy - (alpha * info->z_dx);
1065 		c = 0;
1066 		for (i = info->z_size; i != 0; i--) {
1067 			c += z >> Z_SHIFT;
1068 			z &= Z_MASK;
1069 			idx = (alpha * info->z_size * 2) + i - 1;
1070 			info->z_pcoeff[idx] =
1071 			    z_coeff_interpolate(z, info->z_coeff + c);
1072 			z += info->z_dy;
1073 		}
1074 	}
1075 
1076 #ifndef _KERNEL
1077 	fprintf(stderr, "Polyphase: [%d/%d] %d entries\n",
1078 	    info->z_gx, info->z_gy, info->z_size * info->z_gy * 2);
1079 #endif
1080 
1081 	return (0);
1082 }
1083 
1084 static int
1085 z_resampler_setup(struct pcm_feeder *f)
1086 {
1087 	struct z_info *info;
1088 	int64_t gy2gx_max, gx2gy_max;
1089 	uint32_t format;
1090 	int32_t align, i, z_scale;
1091 	int adaptive;
1092 
1093 	info = f->data;
1094 	z_resampler_reset(info);
1095 
1096 	if (info->src == info->dst)
1097 		return (0);
1098 
1099 	/* Shrink by greatest common divisor. */
1100 	i = z_gcd(info->src, info->dst);
1101 	info->z_gx = info->src / i;
1102 	info->z_gy = info->dst / i;
1103 
1104 	/* Too big, or too small. Bail out. */
1105 	if (!(Z_FACTOR_SAFE(info->z_gx) && Z_FACTOR_SAFE(info->z_gy)))
1106 		return (EINVAL);
1107 
1108 	format = f->desc->in;
1109 	adaptive = 0;
1110 	z_scale = 0;
1111 
1112 	/*
1113 	 * Setup everything: filter length, conversion factor, etc.
1114 	 */
1115 	if (Z_IS_SINC(info)) {
1116 		/*
1117 		 * Downsampling, or upsampling scaling factor. As long as the
1118 		 * factor can be represented by a fraction of 1 << Z_SHIFT,
1119 		 * we're pretty much in business. Scaling is not needed for
1120 		 * upsampling, so we just slap Z_ONE there.
1121 		 */
1122 		if (info->z_gx > info->z_gy)
1123 			/*
1124 			 * If the downsampling ratio is beyond sanity,
1125 			 * enable semi-adaptive mode. Although handling
1126 			 * extreme ratio is possible, the result of the
1127 			 * conversion is just pointless, unworthy,
1128 			 * nonsensical noises, etc.
1129 			 */
1130 			if ((info->z_gx / info->z_gy) > Z_SINC_DOWNMAX)
1131 				z_scale = Z_ONE / Z_SINC_DOWNMAX;
1132 			else
1133 				z_scale = ((uint64_t)info->z_gy << Z_SHIFT) /
1134 				    info->z_gx;
1135 		else
1136 			z_scale = Z_ONE;
1137 
1138 		/*
1139 		 * This is actually impossible, unless anything above
1140 		 * overflow.
1141 		 */
1142 		if (z_scale < 1)
1143 			return (E2BIG);
1144 
1145 		/*
1146 		 * Calculate sample time/coefficients index drift. It is
1147 		 * a constant for upsampling, but downsampling require
1148 		 * heavy duty filtering with possible too long filters.
1149 		 * If anything goes wrong, revisit again and enable
1150 		 * adaptive mode.
1151 		 */
1152 z_setup_adaptive_sinc:
1153 		if (info->z_pcoeff != NULL) {
1154 			free(info->z_pcoeff, M_DEVBUF);
1155 			info->z_pcoeff = NULL;
1156 		}
1157 
1158 		if (adaptive == 0) {
1159 			info->z_dy = z_scale << Z_DRIFT_SHIFT;
1160 			if (info->z_dy < 1)
1161 				return (E2BIG);
1162 			info->z_scale = z_scale;
1163 		} else {
1164 			info->z_dy = Z_FULL_ONE;
1165 			info->z_scale = Z_ONE;
1166 		}
1167 
1168 		/* Smallest drift increment. */
1169 		info->z_dx = info->z_dy / info->z_gy;
1170 
1171 		/*
1172 		 * Overflow or underflow. Try adaptive, let it continue and
1173 		 * retry.
1174 		 */
1175 		if (info->z_dx < 1) {
1176 			if (adaptive == 0) {
1177 				adaptive = 1;
1178 				goto z_setup_adaptive_sinc;
1179 			}
1180 			return (E2BIG);
1181 		}
1182 
1183 		/*
1184 		 * Round back output drift.
1185 		 */
1186 		info->z_dy = info->z_dx * info->z_gy;
1187 
1188 		for (i = 0; i < Z_COEFF_TAB_SIZE; i++) {
1189 			if (Z_SINC_COEFF_IDX(info) != i)
1190 				continue;
1191 			/*
1192 			 * Calculate required filter length and guard
1193 			 * against possible abusive result. Note that
1194 			 * this represents only 1/2 of the entire filter
1195 			 * length.
1196 			 */
1197 			info->z_size = z_resampler_sinc_len(info);
1198 
1199 			/*
1200 			 * Multiple of 2 rounding, for better accumulator
1201 			 * performance.
1202 			 */
1203 			info->z_size &= ~1;
1204 
1205 			if (info->z_size < 2 || info->z_size > Z_SINC_MAX) {
1206 				if (adaptive == 0) {
1207 					adaptive = 1;
1208 					goto z_setup_adaptive_sinc;
1209 				}
1210 				return (E2BIG);
1211 			}
1212 			info->z_coeff = z_coeff_tab[i].coeff + Z_COEFF_OFFSET;
1213 			info->z_dcoeff = z_coeff_tab[i].dcoeff;
1214 			break;
1215 		}
1216 
1217 		if (info->z_coeff == NULL || info->z_dcoeff == NULL)
1218 			return (EINVAL);
1219 	} else if (Z_IS_LINEAR(info)) {
1220 		/*
1221 		 * Don't put much effort if we're doing linear interpolation.
1222 		 * Just center the interpolation distance within Z_LINEAR_ONE,
1223 		 * and be happy about it.
1224 		 */
1225 		info->z_dx = Z_LINEAR_FULL_ONE / info->z_gy;
1226 	}
1227 
1228 	/*
1229 	 * We're safe for now, lets continue.. Look for our resampler
1230 	 * depending on configured format and quality.
1231 	 */
1232 	for (i = 0; i < Z_RESAMPLER_TAB_SIZE; i++) {
1233 		int ridx;
1234 
1235 		if (AFMT_ENCODING(format) != z_resampler_tab[i].format)
1236 			continue;
1237 		if (Z_IS_SINC(info) && adaptive == 0 &&
1238 		    z_resampler_build_polyphase(info) == 0)
1239 			ridx = Z_RESAMPLER_SINC_POLYPHASE;
1240 		else
1241 			ridx = Z_RESAMPLER_IDX(info);
1242 		info->z_resample = z_resampler_tab[i].resampler[ridx];
1243 		break;
1244 	}
1245 
1246 	if (info->z_resample == NULL)
1247 		return (EINVAL);
1248 
1249 	info->bps = AFMT_BPS(format);
1250 	align = info->channels * info->bps;
1251 
1252 	/*
1253 	 * Calculate largest value that can be fed into z_gy2gx() and
1254 	 * z_gx2gy() without causing (signed) 32bit overflow. z_gy2gx() will
1255 	 * be called early during feeding process to determine how much input
1256 	 * samples that is required to generate requested output, while
1257 	 * z_gx2gy() will be called just before samples filtering /
1258 	 * accumulation process based on available samples that has been
1259 	 * calculated using z_gx2gy().
1260 	 *
1261 	 * Now that is damn confusing, I guess ;-) .
1262 	 */
1263 	gy2gx_max = (((uint64_t)info->z_gy * INT32_MAX) - info->z_gy + 1) /
1264 	    info->z_gx;
1265 
1266 	if ((gy2gx_max * align) > SND_FXDIV_MAX)
1267 		gy2gx_max = SND_FXDIV_MAX / align;
1268 
1269 	if (gy2gx_max < 1)
1270 		return (E2BIG);
1271 
1272 	gx2gy_max = (((uint64_t)info->z_gx * INT32_MAX) - info->z_gy) /
1273 	    info->z_gy;
1274 
1275 	if (gx2gy_max > INT32_MAX)
1276 		gx2gy_max = INT32_MAX;
1277 
1278 	if (gx2gy_max < 1)
1279 		return (E2BIG);
1280 
1281 	/*
1282 	 * Ensure that z_gy2gx() at its largest possible calculated value
1283 	 * (alpha = 0) will not cause overflow further late during z_gx2gy()
1284 	 * stage.
1285 	 */
1286 	if (z_gy2gx(info, gy2gx_max) > _Z_GCAST(gx2gy_max))
1287 		return (E2BIG);
1288 
1289 	info->z_maxfeed = gy2gx_max * align;
1290 
1291 #ifdef Z_USE_ALPHADRIFT
1292 	info->z_startdrift = z_gy2gx(info, 1);
1293 	info->z_alphadrift = z_drift(info, info->z_startdrift, 1);
1294 #endif
1295 
1296 	i = z_gy2gx(info, 1);
1297 	info->z_full = z_roundpow2((info->z_size << 1) + i);
1298 
1299 	/*
1300 	 * Too big to be true, and overflowing left and right like mad ..
1301 	 */
1302 	if ((info->z_full * align) < 1) {
1303 		if (adaptive == 0 && Z_IS_SINC(info)) {
1304 			adaptive = 1;
1305 			goto z_setup_adaptive_sinc;
1306 		}
1307 		return (E2BIG);
1308 	}
1309 
1310 	/*
1311 	 * Increase full buffer size if its too small to reduce cyclic
1312 	 * buffer shifting in main conversion/feeder loop.
1313 	 */
1314 	while (info->z_full < Z_RESERVOIR_MAX &&
1315 	    (info->z_full - (info->z_size << 1)) < Z_RESERVOIR)
1316 		info->z_full <<= 1;
1317 
1318 	/* Initialize buffer position. */
1319 	info->z_mask = info->z_full - 1;
1320 	info->z_start = z_prev(info, info->z_size << 1, 1);
1321 	info->z_pos = z_next(info, info->z_start, 1);
1322 
1323 	/*
1324 	 * Allocate or reuse delay line buffer, whichever makes sense.
1325 	 */
1326 	i = info->z_full * align;
1327 	if (i < 1)
1328 		return (E2BIG);
1329 
1330 	if (info->z_delay == NULL || info->z_alloc < i ||
1331 	    i <= (info->z_alloc >> 1)) {
1332 		if (info->z_delay != NULL)
1333 			free(info->z_delay, M_DEVBUF);
1334 		info->z_delay = malloc(i, M_DEVBUF, M_NOWAIT | M_ZERO);
1335 		if (info->z_delay == NULL)
1336 			return (ENOMEM);
1337 		info->z_alloc = i;
1338 	}
1339 
1340 	/*
1341 	 * Zero out head of buffer to avoid pops and clicks.
1342 	 */
1343 	memset(info->z_delay, sndbuf_zerodata(f->desc->out),
1344 	    info->z_pos * align);
1345 
1346 #ifdef Z_DIAGNOSTIC
1347 	/*
1348 	 * XXX Debuging mess !@#$%^
1349 	 */
1350 #define dumpz(x)	fprintf(stderr, "\t%12s = %10u : %-11d\n",	\
1351 			    "z_"__STRING(x), (uint32_t)info->z_##x,	\
1352 			    (int32_t)info->z_##x)
1353 	fprintf(stderr, "\n%s():\n", __func__);
1354 	fprintf(stderr, "\tchannels=%d, bps=%d, format=0x%08x, quality=%d\n",
1355 	    info->channels, info->bps, format, info->quality);
1356 	fprintf(stderr, "\t%d (%d) -> %d (%d), ",
1357 	    info->src, info->rsrc, info->dst, info->rdst);
1358 	fprintf(stderr, "[%d/%d]\n", info->z_gx, info->z_gy);
1359 	fprintf(stderr, "\tminreq=%d, ", z_gy2gx(info, 1));
1360 	if (adaptive != 0)
1361 		z_scale = Z_ONE;
1362 	fprintf(stderr, "factor=0x%08x/0x%08x (%f)\n",
1363 	    z_scale, Z_ONE, (double)z_scale / Z_ONE);
1364 	fprintf(stderr, "\tbase_length=%d, ", Z_SINC_BASE_LEN(info));
1365 	fprintf(stderr, "adaptive=%s\n", (adaptive != 0) ? "YES" : "NO");
1366 	dumpz(size);
1367 	dumpz(alloc);
1368 	if (info->z_alloc < 1024)
1369 		fprintf(stderr, "\t%15s%10d Bytes\n",
1370 		    "", info->z_alloc);
1371 	else if (info->z_alloc < (1024 << 10))
1372 		fprintf(stderr, "\t%15s%10d KBytes\n",
1373 		    "", info->z_alloc >> 10);
1374 	else if (info->z_alloc < (1024 << 20))
1375 		fprintf(stderr, "\t%15s%10d MBytes\n",
1376 		    "", info->z_alloc >> 20);
1377 	else
1378 		fprintf(stderr, "\t%15s%10d GBytes\n",
1379 		    "", info->z_alloc >> 30);
1380 	fprintf(stderr, "\t%12s   %10d (min output samples)\n",
1381 	    "",
1382 	    (int32_t)z_gx2gy(info, info->z_full - (info->z_size << 1)));
1383 	fprintf(stderr, "\t%12s   %10d (min allocated output samples)\n",
1384 	    "",
1385 	    (int32_t)z_gx2gy(info, (info->z_alloc / align) -
1386 	    (info->z_size << 1)));
1387 	fprintf(stderr, "\t%12s = %10d\n",
1388 	    "z_gy2gx()", (int32_t)z_gy2gx(info, 1));
1389 	fprintf(stderr, "\t%12s = %10d -> z_gy2gx() -> %d\n",
1390 	    "Max", (int32_t)gy2gx_max, (int32_t)z_gy2gx(info, gy2gx_max));
1391 	fprintf(stderr, "\t%12s = %10d\n",
1392 	    "z_gx2gy()", (int32_t)z_gx2gy(info, 1));
1393 	fprintf(stderr, "\t%12s = %10d -> z_gx2gy() -> %d\n",
1394 	    "Max", (int32_t)gx2gy_max, (int32_t)z_gx2gy(info, gx2gy_max));
1395 	dumpz(maxfeed);
1396 	dumpz(full);
1397 	dumpz(start);
1398 	dumpz(pos);
1399 	dumpz(scale);
1400 	fprintf(stderr, "\t%12s   %10f\n", "",
1401 	    (double)info->z_scale / Z_ONE);
1402 	dumpz(dx);
1403 	fprintf(stderr, "\t%12s   %10f\n", "",
1404 	    (double)info->z_dx / info->z_dy);
1405 	dumpz(dy);
1406 	fprintf(stderr, "\t%12s   %10d (drift step)\n", "",
1407 	    info->z_dy >> Z_SHIFT);
1408 	fprintf(stderr, "\t%12s   %10d (scaling differences)\n", "",
1409 	    (z_scale << Z_DRIFT_SHIFT) - info->z_dy);
1410 	fprintf(stderr, "\t%12s = %u bytes\n",
1411 	    "intpcm32_t", sizeof(intpcm32_t));
1412 	fprintf(stderr, "\t%12s = 0x%08x, smallest=%.16lf\n",
1413 	    "Z_ONE", Z_ONE, (double)1.0 / (double)Z_ONE);
1414 #endif
1415 
1416 	return (0);
1417 }
1418 
1419 static int
1420 z_resampler_set(struct pcm_feeder *f, int what, int32_t value)
1421 {
1422 	struct z_info *info;
1423 	int32_t oquality;
1424 
1425 	info = f->data;
1426 
1427 	switch (what) {
1428 	case Z_RATE_SRC:
1429 		if (value < feeder_rate_min || value > feeder_rate_max)
1430 			return (E2BIG);
1431 		if (value == info->rsrc)
1432 			return (0);
1433 		info->rsrc = value;
1434 		break;
1435 	case Z_RATE_DST:
1436 		if (value < feeder_rate_min || value > feeder_rate_max)
1437 			return (E2BIG);
1438 		if (value == info->rdst)
1439 			return (0);
1440 		info->rdst = value;
1441 		break;
1442 	case Z_RATE_QUALITY:
1443 		if (value < Z_QUALITY_MIN || value > Z_QUALITY_MAX)
1444 			return (EINVAL);
1445 		if (value == info->quality)
1446 			return (0);
1447 		/*
1448 		 * If we failed to set the requested quality, restore
1449 		 * the old one. We cannot afford leaving it broken since
1450 		 * passive feeder chains like vchans never reinitialize
1451 		 * itself.
1452 		 */
1453 		oquality = info->quality;
1454 		info->quality = value;
1455 		if (z_resampler_setup(f) == 0)
1456 			return (0);
1457 		info->quality = oquality;
1458 		break;
1459 	case Z_RATE_CHANNELS:
1460 		if (value < SND_CHN_MIN || value > SND_CHN_MAX)
1461 			return (EINVAL);
1462 		if (value == info->channels)
1463 			return (0);
1464 		info->channels = value;
1465 		break;
1466 	default:
1467 		return (EINVAL);
1468 		break;
1469 	}
1470 
1471 	return (z_resampler_setup(f));
1472 }
1473 
1474 static int
1475 z_resampler_get(struct pcm_feeder *f, int what)
1476 {
1477 	struct z_info *info;
1478 
1479 	info = f->data;
1480 
1481 	switch (what) {
1482 	case Z_RATE_SRC:
1483 		return (info->rsrc);
1484 		break;
1485 	case Z_RATE_DST:
1486 		return (info->rdst);
1487 		break;
1488 	case Z_RATE_QUALITY:
1489 		return (info->quality);
1490 		break;
1491 	case Z_RATE_CHANNELS:
1492 		return (info->channels);
1493 		break;
1494 	default:
1495 		break;
1496 	}
1497 
1498 	return (-1);
1499 }
1500 
1501 static int
1502 z_resampler_init(struct pcm_feeder *f)
1503 {
1504 	struct z_info *info;
1505 	int ret;
1506 
1507 	if (f->desc->in != f->desc->out)
1508 		return (EINVAL);
1509 
1510 	info = malloc(sizeof(*info), M_DEVBUF, M_NOWAIT | M_ZERO);
1511 	if (info == NULL)
1512 		return (ENOMEM);
1513 
1514 	info->rsrc = Z_RATE_DEFAULT;
1515 	info->rdst = Z_RATE_DEFAULT;
1516 	info->quality = feeder_rate_quality;
1517 	info->channels = AFMT_CHANNEL(f->desc->in);
1518 
1519 	f->data = info;
1520 
1521 	ret = z_resampler_setup(f);
1522 	if (ret != 0) {
1523 		if (info->z_pcoeff != NULL)
1524 			free(info->z_pcoeff, M_DEVBUF);
1525 		if (info->z_delay != NULL)
1526 			free(info->z_delay, M_DEVBUF);
1527 		free(info, M_DEVBUF);
1528 		f->data = NULL;
1529 	}
1530 
1531 	return (ret);
1532 }
1533 
1534 static int
1535 z_resampler_free(struct pcm_feeder *f)
1536 {
1537 	struct z_info *info;
1538 
1539 	info = f->data;
1540 	if (info != NULL) {
1541 		if (info->z_pcoeff != NULL)
1542 			free(info->z_pcoeff, M_DEVBUF);
1543 		if (info->z_delay != NULL)
1544 			free(info->z_delay, M_DEVBUF);
1545 		free(info, M_DEVBUF);
1546 	}
1547 
1548 	f->data = NULL;
1549 
1550 	return (0);
1551 }
1552 
1553 static uint32_t
1554 z_resampler_feed_internal(struct pcm_feeder *f, struct pcm_channel *c,
1555     uint8_t *b, uint32_t count, void *source)
1556 {
1557 	struct z_info *info;
1558 	int32_t alphadrift, startdrift, reqout, ocount, reqin, align;
1559 	int32_t fetch, fetched, start, cp;
1560 	uint8_t *dst;
1561 
1562 	info = f->data;
1563 	if (info->z_resample == NULL)
1564 		return (z_feed(f->source, c, b, count, source));
1565 
1566 	/*
1567 	 * Calculate sample size alignment and amount of sample output.
1568 	 * We will do everything in sample domain, but at the end we
1569 	 * will jump back to byte domain.
1570 	 */
1571 	align = info->channels * info->bps;
1572 	ocount = SND_FXDIV(count, align);
1573 	if (ocount == 0)
1574 		return (0);
1575 
1576 	/*
1577 	 * Calculate amount of input samples that is needed to generate
1578 	 * exact amount of output.
1579 	 */
1580 	reqin = z_gy2gx(info, ocount) - z_fetched(info);
1581 
1582 #ifdef Z_USE_ALPHADRIFT
1583 	startdrift = info->z_startdrift;
1584 	alphadrift = info->z_alphadrift;
1585 #else
1586 	startdrift = _Z_GY2GX(info, 0, 1);
1587 	alphadrift = z_drift(info, startdrift, 1);
1588 #endif
1589 
1590 	dst = b;
1591 
1592 	do {
1593 		if (reqin != 0) {
1594 			fetch = z_min(z_free(info), reqin);
1595 			if (fetch == 0) {
1596 				/*
1597 				 * No more free spaces, so wind enough
1598 				 * samples back to the head of delay line
1599 				 * in byte domain.
1600 				 */
1601 				fetched = z_fetched(info);
1602 				start = z_prev(info, info->z_start,
1603 				    (info->z_size << 1) - 1);
1604 				cp = (info->z_size << 1) + fetched;
1605 				z_copy(info->z_delay + (start * align),
1606 				    info->z_delay, cp * align);
1607 				info->z_start =
1608 				    z_prev(info, info->z_size << 1, 1);
1609 				info->z_pos =
1610 				    z_next(info, info->z_start, fetched + 1);
1611 				fetch = z_min(z_free(info), reqin);
1612 #ifdef Z_DIAGNOSTIC
1613 				if (1) {
1614 					static uint32_t kk = 0;
1615 					fprintf(stderr,
1616 					    "Buffer Move: "
1617 					    "start=%d fetched=%d cp=%d "
1618 					    "cycle=%u [%u]\r",
1619 					    start, fetched, cp, info->z_cycle,
1620 					    ++kk);
1621 				}
1622 				info->z_cycle = 0;
1623 #endif
1624 			}
1625 			if (fetch != 0) {
1626 				/*
1627 				 * Fetch in byte domain and jump back
1628 				 * to sample domain.
1629 				 */
1630 				fetched = SND_FXDIV(z_feed(f->source, c,
1631 				    info->z_delay + (info->z_pos * align),
1632 				    fetch * align, source), align);
1633 				/*
1634 				 * Prepare to convert fetched buffer,
1635 				 * or mark us done if we cannot fulfill
1636 				 * the request.
1637 				 */
1638 				reqin -= fetched;
1639 				info->z_pos += fetched;
1640 				if (fetched != fetch)
1641 					reqin = 0;
1642 			}
1643 		}
1644 
1645 		reqout = z_min(z_gx2gy(info, z_fetched(info)), ocount);
1646 		if (reqout != 0) {
1647 			ocount -= reqout;
1648 
1649 			/*
1650 			 * Drift.. drift.. drift..
1651 			 *
1652 			 * Notice that there are 2 methods of doing the drift
1653 			 * operations: The former is much cleaner (in a sense
1654 			 * of mathematical readings of my eyes), but slower
1655 			 * due to integer division in z_gy2gx(). Nevertheless,
1656 			 * both should give the same exact accurate drifting
1657 			 * results, so the later is favourable.
1658 			 */
1659 			do {
1660 				info->z_resample(info, dst);
1661 				info->z_alpha += alphadrift;
1662 				if (info->z_alpha < info->z_gy)
1663 					info->z_start += startdrift;
1664 				else {
1665 					info->z_start += startdrift - 1;
1666 					info->z_alpha -= info->z_gy;
1667 				}
1668 				dst += align;
1669 #ifdef Z_DIAGNOSTIC
1670 				info->z_cycle++;
1671 #endif
1672 			} while (--reqout != 0);
1673 		}
1674 	} while (reqin != 0 && ocount != 0);
1675 
1676 	/*
1677 	 * Back to byte domain..
1678 	 */
1679 	return (dst - b);
1680 }
1681 
1682 static int
1683 z_resampler_feed(struct pcm_feeder *f, struct pcm_channel *c, uint8_t *b,
1684     uint32_t count, void *source)
1685 {
1686 	uint32_t feed, maxfeed, left;
1687 
1688 	/*
1689 	 * Split count to smaller chunks to avoid possible 32bit overflow.
1690 	 */
1691 	maxfeed = ((struct z_info *)(f->data))->z_maxfeed;
1692 	left = count;
1693 
1694 	do {
1695 		feed = z_resampler_feed_internal(f, c, b,
1696 		    z_min(maxfeed, left), source);
1697 		b += feed;
1698 		left -= feed;
1699 	} while (left != 0 && feed != 0);
1700 
1701 	return (count - left);
1702 }
1703 
1704 static struct pcm_feederdesc feeder_rate_desc[] = {
1705 	{ FEEDER_RATE, 0, 0, 0, 0 },
1706 	{ 0, 0, 0, 0, 0 },
1707 };
1708 
1709 static kobj_method_t feeder_rate_methods[] = {
1710 	KOBJMETHOD(feeder_init,		z_resampler_init),
1711 	KOBJMETHOD(feeder_free,		z_resampler_free),
1712 	KOBJMETHOD(feeder_set,		z_resampler_set),
1713 	KOBJMETHOD(feeder_get,		z_resampler_get),
1714 	KOBJMETHOD(feeder_feed,		z_resampler_feed),
1715 	KOBJMETHOD_END
1716 };
1717 
1718 FEEDER_DECLARE(feeder_rate, NULL);
1719