forked from BleepLabs/Audio
-
Notifications
You must be signed in to change notification settings - Fork 0
/
synth_pinknoise.cpp
148 lines (137 loc) · 5.66 KB
/
synth_pinknoise.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
/* Audio Library for Teensy 3.X
* Copyright (c) 2014, Paul Stoffregen, [email protected]
*
* Development of this audio library was funded by PJRC.COM, LLC by sales of
* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
* open source software by purchasing Teensy or other PJRC products.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice, development funding notice, and this permission
* notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// http://stenzel.waldorfmusic.de/post/pink/
// https://github.com/Stenzel/newshadeofpink
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// New Shade of Pink
// (c) 2014 Stefan Stenzel
// stefan at waldorfmusic.de
//
// Terms of use:
// Use for any purpose. If used in a commercial product, you should give me one.
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#include "synth_pinknoise.h"
int16_t AudioSynthNoisePink::instance_cnt = 0;
// Let preprocessor and compiler calculate two lookup tables for 12-tap FIR Filter
// with these coefficients: 1.190566, 0.162580, 0.002208, 0.025475, -0.001522,
// 0.007322, 0.001774, 0.004529, -0.001561, 0.000776, -0.000486, 0.002017
#define Fn(cf,m,shift) (2048*cf*(2*((m)>>shift&1)-1))
#define FA(n) (int32_t)(Fn(1.190566,n,0)+Fn(0.162580,n,1)+Fn(0.002208,n,2)+\
Fn(0.025475,n,3)+Fn(-0.001522,n,4)+Fn(0.007322,n,5))
#define FB(n) (int32_t)(Fn(0.001774,n,0)+Fn(0.004529,n,1)+Fn(-0.001561,n,2)+\
Fn(0.000776,n,3)+Fn(-0.000486,n,4)+Fn(0.002017,n,5))
#define FA8(n) FA(n),FA(n+1),FA(n+2),FA(n+3),FA(n+4),FA(n+5),FA(n+6),FA(n+7)
#define FB8(n) FB(n),FB(n+1),FB(n+2),FB(n+3),FB(n+4),FB(n+5),FB(n+6),FB(n+7)
const int32_t AudioSynthNoisePink::pfira[64] = // 1st FIR lookup table
{FA8(0),FA8(8),FA8(16),FA8(24),FA8(32),FA8(40),FA8(48),FA8(56)};
const int32_t AudioSynthNoisePink::pfirb[64] = // 2nd FIR lookup table
{FB8(0),FB8(8),FB8(16),FB8(24),FB8(32),FB8(40),FB8(48),FB8(56)};
// bitreversed lookup table
#define PM16(n) n,0x80,0x40,0x80,0x20,0x80,0x40,0x80,0x10,0x80,0x40,0x80,0x20,0x80,0x40,0x80
const uint8_t AudioSynthNoisePink::pnmask[256] = {
PM16(0),PM16(8),PM16(4),PM16(8),PM16(2),PM16(8),PM16(4),PM16(8),
PM16(1),PM16(8),PM16(4),PM16(8),PM16(2),PM16(8),PM16(4),PM16(8)
};
#define PINT(bitmask, out) /* macro for processing: */\
bit = lfsr >> 31; /* spill random to all bits */\
dec &= ~bitmask; /* blank old decrement bit */\
lfsr <<= 1; /* shift lfsr */\
dec |= inc & bitmask; /* copy increment to decrement bit */\
inc ^= bit & bitmask; /* new random bit */\
accu += inc - dec; /* integrate */\
lfsr ^= bit & taps; /* update lfsr */\
out = accu + /* save output */\
pfira[lfsr & 0x3F] + /* add 1st half precalculated FIR */\
pfirb[lfsr >> 6 & 0x3F] /* add 2nd half, also correts bias */
void AudioSynthNoisePink::update(void)
{
audio_block_t *block;
uint32_t *p, *end;
int32_t n1, n2;
int32_t gain;
int32_t inc, dec, accu, bit, lfsr;
int32_t taps;
gain = level;
if (gain == 0) return;
block = allocate();
if (!block) return;
p = (uint32_t *)(block->data);
end = p + AUDIO_BLOCK_SAMPLES/2;
taps = 0x46000001;
inc = pinc;
dec = pdec;
accu = paccu;
lfsr = plfsr;
do {
int32_t mask = pnmask[pncnt++];
PINT(mask, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0400, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0200, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0400, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0100, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0400, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0200, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
PINT(0x0400, n1);
n1 = signed_multiply_32x16b(gain, n1);
PINT(0x0800, n2);
n2 = signed_multiply_32x16b(gain, n2);
*p++ = pack_16b_16b(n2, n1);
} while (p < end);
pinc = inc;
pdec = dec;
paccu = accu;
plfsr = lfsr;
transmit(block);
release(block);
}