libsidplayfp 1.0.3
ExternalFilter.h
00001 /*
00002  * This file is part of libsidplayfp, a SID player engine.
00003  *
00004  * Copyright 2011-2013 Leandro Nini <drfiemost@users.sourceforge.net>
00005  * Copyright 2007-2010 Antti Lankila
00006  * Copyright 2004 Dag Lem <resid@nimrod.no>
00007  *
00008  * This program is free software; you can redistribute it and/or modify
00009  * it under the terms of the GNU General Public License as published by
00010  * the Free Software Foundation; either version 2 of the License, or
00011  * (at your option) any later version.
00012  *
00013  * This program is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU General Public License
00019  * along with this program; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
00021  */
00022 
00023 #ifndef EXTERNALFILTER_H
00024 #define EXTERNALFILTER_H
00025 
00026 #include "siddefs-fp.h"
00027 
00028 namespace reSIDfp
00029 {
00030 
00051 class ExternalFilter
00052 {
00053 private:
00057     int Vlp;
00058 
00062     int Vhp;
00063 
00064     int w0lp_1_s7;
00065 
00066     int w0hp_1_s17;
00067 
00068 public:
00074     int clock(int Vi);
00075 
00079     ExternalFilter();
00080 
00086     void setClockFrequency(double frequency);
00087 
00091     void reset();
00092 };
00093 
00094 } // namespace reSIDfp
00095 
00096 #if RESID_INLINING || defined(EXTERNALFILTER_CPP)
00097 
00098 namespace reSIDfp
00099 {
00100 
00101 RESID_INLINE
00102 int ExternalFilter::clock(int Vi)
00103 {
00104     const int dVlp = (w0lp_1_s7 * ((Vi << 11) - Vlp) >> 7);
00105     const int dVhp = (w0hp_1_s17 * (Vlp - Vhp) >> 17);
00106     Vlp += dVlp;
00107     Vhp += dVhp;
00108     return (Vlp - Vhp) >> 11;
00109 }
00110 
00111 } // namespace reSIDfp
00112 
00113 #endif
00114 
00115 #endif