libsidplayfp  2.1.0
ExternalFilter.h
1 /*
2  * This file is part of libsidplayfp, a SID player engine.
3  *
4  * Copyright 2011-2020 Leandro Nini <drfiemost@users.sourceforge.net>
5  * Copyright 2007-2010 Antti Lankila
6  * Copyright 2004 Dag Lem <resid@nimrod.no>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21  */
22 
23 #ifndef EXTERNALFILTER_H
24 #define EXTERNALFILTER_H
25 
26 #include "siddefs-fp.h"
27 
28 namespace reSIDfp
29 {
30 
63 {
64 private:
66  int Vlp;
67 
69  int Vhp;
70 
71  int w0lp_1_s7;
72 
73  int w0hp_1_s17;
74 
75 public:
81  int clock(unsigned short input);
82 
87 
93  void setClockFrequency(double frequency);
94 
98  void reset();
99 };
100 
101 } // namespace reSIDfp
102 
103 #if RESID_INLINING || defined(EXTERNALFILTER_CPP)
104 
105 namespace reSIDfp
106 {
107 
108 RESID_INLINE
109 int ExternalFilter::clock(unsigned short input)
110 {
111  const int Vi = (static_cast<unsigned int>(input)<<11) - (1 << (11+15));
112  const int dVlp = (w0lp_1_s7 * (Vi - Vlp) >> 7);
113  const int dVhp = (w0hp_1_s17 * (Vlp - Vhp) >> 17);
114  Vlp += dVlp;
115  Vhp += dVhp;
116  return (Vlp - Vhp) >> 11;
117 }
118 
119 } // namespace reSIDfp
120 
121 #endif
122 
123 #endif
Definition: ExternalFilter.h:63
void reset()
Definition: ExternalFilter.cpp:61
void setClockFrequency(double frequency)
Definition: ExternalFilter.cpp:48
ExternalFilter()
Definition: ExternalFilter.cpp:41
int clock(unsigned short input)
Definition: ExternalFilter.h:109