xref: /openbmc/linux/sound/isa/gus/gus_volume.c (revision 64d85cc9)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  */
5 
6 #include <linux/time.h>
7 #include <linux/export.h>
8 #include <sound/core.h>
9 #include <sound/gus.h>
10 #define __GUS_TABLES_ALLOC__
11 #include "gus_tables.h"
12 
13 EXPORT_SYMBOL(snd_gf1_atten_table); /* for snd-gus-synth module */
14 
15 unsigned short snd_gf1_lvol_to_gvol_raw(unsigned int vol)
16 {
17 	unsigned short e, m, tmp;
18 
19 	if (vol > 65535)
20 		vol = 65535;
21 	tmp = vol;
22 	e = 7;
23 	if (tmp < 128) {
24 		while (e > 0 && tmp < (1 << e))
25 			e--;
26 	} else {
27 		while (tmp > 255) {
28 			tmp >>= 1;
29 			e++;
30 		}
31 	}
32 	m = vol - (1 << e);
33 	if (m > 0) {
34 		if (e > 8)
35 			m >>= e - 8;
36 		else if (e < 8)
37 			m <<= 8 - e;
38 		m &= 255;
39 	}
40 	return (e << 8) | m;
41 }
42 
43 #if 0
44 
45 unsigned int snd_gf1_gvol_to_lvol_raw(unsigned short gf1_vol)
46 {
47 	unsigned int rvol;
48 	unsigned short e, m;
49 
50 	if (!gf1_vol)
51 		return 0;
52 	e = gf1_vol >> 8;
53 	m = (unsigned char) gf1_vol;
54 	rvol = 1 << e;
55 	if (e > 8)
56 		return rvol | (m << (e - 8));
57 	return rvol | (m >> (8 - e));
58 }
59 
60 unsigned int snd_gf1_calc_ramp_rate(struct snd_gus_card * gus,
61 				    unsigned short start,
62 				    unsigned short end,
63 				    unsigned int us)
64 {
65 	static unsigned char vol_rates[19] =
66 	{
67 		23, 24, 26, 28, 29, 31, 32, 34,
68 		36, 37, 39, 40, 42, 44, 45, 47,
69 		49, 50, 52
70 	};
71 	unsigned short range, increment, value, i;
72 
73 	start >>= 4;
74 	end >>= 4;
75 	if (start < end)
76 		us /= end - start;
77 	else
78 		us /= start - end;
79 	range = 4;
80 	value = gus->gf1.enh_mode ?
81 	    vol_rates[0] :
82 	    vol_rates[gus->gf1.active_voices - 14];
83 	for (i = 0; i < 3; i++) {
84 		if (us < value) {
85 			range = i;
86 			break;
87 		} else
88 			value <<= 3;
89 	}
90 	if (range == 4) {
91 		range = 3;
92 		increment = 1;
93 	} else
94 		increment = (value + (value >> 1)) / us;
95 	return (range << 6) | (increment & 0x3f);
96 }
97 
98 #endif  /*  0  */
99 
100 unsigned short snd_gf1_translate_freq(struct snd_gus_card * gus, unsigned int freq16)
101 {
102 	freq16 >>= 3;
103 	if (freq16 < 50)
104 		freq16 = 50;
105 	if (freq16 & 0xf8000000) {
106 		freq16 = ~0xf8000000;
107 		snd_printk(KERN_ERR "snd_gf1_translate_freq: overflow - freq = 0x%x\n", freq16);
108 	}
109 	return ((freq16 << 9) + (gus->gf1.playback_freq >> 1)) / gus->gf1.playback_freq;
110 }
111 
112 #if 0
113 
114 short snd_gf1_compute_vibrato(short cents, unsigned short fc_register)
115 {
116 	static short vibrato_table[] =
117 	{
118 		0, 0, 32, 592, 61, 1175, 93, 1808,
119 		124, 2433, 152, 3007, 182, 3632, 213, 4290,
120 		241, 4834, 255, 5200
121 	};
122 
123 	long depth;
124 	short *vi1, *vi2, pcents, v1;
125 
126 	pcents = cents < 0 ? -cents : cents;
127 	for (vi1 = vibrato_table, vi2 = vi1 + 2; pcents > *vi2; vi1 = vi2, vi2 += 2);
128 	v1 = *(vi1 + 1);
129 	/* The FC table above is a list of pairs. The first number in the pair     */
130 	/* is the cents index from 0-255 cents, and the second number in the       */
131 	/* pair is the FC adjustment needed to change the pitch by the indexed     */
132 	/* number of cents. The table was created for an FC of 32768.              */
133 	/* The following expression does a linear interpolation against the        */
134 	/* approximated log curve in the table above, and then scales the number   */
135 	/* by the FC before the LFO. This calculation also adjusts the output      */
136 	/* value to produce the appropriate depth for the hardware. The depth      */
137 	/* is 2 * desired FC + 1.                                                  */
138 	depth = (((int) (*(vi2 + 1) - *vi1) * (pcents - *vi1) / (*vi2 - *vi1)) + v1) * fc_register >> 14;
139 	if (depth)
140 		depth++;
141 	if (depth > 255)
142 		depth = 255;
143 	return cents < 0 ? -(short) depth : (short) depth;
144 }
145 
146 unsigned short snd_gf1_compute_pitchbend(unsigned short pitchbend, unsigned short sens)
147 {
148 	static long log_table[] = {1024, 1085, 1149, 1218, 1290, 1367, 1448, 1534, 1625, 1722, 1825, 1933};
149 	int wheel, sensitivity;
150 	unsigned int mantissa, f1, f2;
151 	unsigned short semitones, f1_index, f2_index, f1_power, f2_power;
152 	char bend_down = 0;
153 	int bend;
154 
155 	if (!sens)
156 		return 1024;
157 	wheel = (int) pitchbend - 8192;
158 	sensitivity = ((int) sens * wheel) / 128;
159 	if (sensitivity < 0) {
160 		bend_down = 1;
161 		sensitivity = -sensitivity;
162 	}
163 	semitones = (unsigned int) (sensitivity >> 13);
164 	mantissa = sensitivity % 8192;
165 	f1_index = semitones % 12;
166 	f2_index = (semitones + 1) % 12;
167 	f1_power = semitones / 12;
168 	f2_power = (semitones + 1) / 12;
169 	f1 = log_table[f1_index] << f1_power;
170 	f2 = log_table[f2_index] << f2_power;
171 	bend = (int) ((((f2 - f1) * mantissa) >> 13) + f1);
172 	if (bend_down)
173 		bend = 1048576L / bend;
174 	return bend;
175 }
176 
177 unsigned short snd_gf1_compute_freq(unsigned int freq,
178 				    unsigned int rate,
179 				    unsigned short mix_rate)
180 {
181 	unsigned int fc;
182 	int scale = 0;
183 
184 	while (freq >= 4194304L) {
185 		scale++;
186 		freq >>= 1;
187 	}
188 	fc = (freq << 10) / rate;
189 	if (fc > 97391L) {
190 		fc = 97391;
191 		snd_printk(KERN_ERR "patch: (1) fc frequency overflow - %u\n", fc);
192 	}
193 	fc = (fc * 44100UL) / mix_rate;
194 	while (scale--)
195 		fc <<= 1;
196 	if (fc > 65535L) {
197 		fc = 65535;
198 		snd_printk(KERN_ERR "patch: (2) fc frequency overflow - %u\n", fc);
199 	}
200 	return (unsigned short) fc;
201 }
202 
203 #endif  /*  0  */
204