1 //  ---------------------------------------------------------------------------
2 //  This file is part of reSID, a MOS6581 SID emulator engine.
3 //  Copyright (C) 2004  Dag Lem <resid@nimrod.no>
4 //
5 //  This program is free software; you can redistribute it and/or modify
6 //  it under the terms of the GNU General Public License as published by
7 //  the Free Software Foundation; either version 2 of the License, or
8 //  (at your option) any later version.
9 //
10 //  This program is distributed in the hope that it will be useful,
11 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
12 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 //  GNU General Public License for more details.
14 //
15 //  You should have received a copy of the GNU General Public License
16 //  along with this program; if not, write to the Free Software
17 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18 //  ---------------------------------------------------------------------------
19 
20 #ifndef __SID_H__
21 #define __SID_H__
22 
23 #include "siddefs.h"
24 #include "voice.h"
25 #include "filter.h"
26 #include "extfilt.h"
27 #include "pot.h"
28 
29 class cSID
30 {
31 public:
32   cSID();
33   ~cSID();
34 
35   void set_chip_model(chip_model model);
36   void enable_filter(bool enable);
37   void enable_external_filter(bool enable);
38   bool set_sampling_parameters(double clock_freq, sampling_method method,
39 			       double sample_freq, double pass_freq = -1,
40 			       double filter_scale = 0.97);
41   void adjust_sampling_frequency(double sample_freq);
42 
43   void fc_default(const fc_point*& points, int& count);
44   PointPlotter<sound_sample> fc_plotter();
45 
46   void clock();
47   void clock(cycle_count delta_t);
48   int clock(cycle_count& delta_t, short* buf, int n, int interleave = 1);
49   void reset();
50 
51   // Read/write registers.
52   reg8 read(reg8 offset);
53   void write(reg8 offset, reg8 value);
54 
55   // Read/write state.
56   class State
57   {
58   public:
59     State();
60 
61     char sid_register[0x20];
62 
63     reg8 bus_value;
64     cycle_count bus_value_ttl;
65 
66     reg24 accumulator[3];
67     reg24 shift_register[3];
68     reg16 rate_counter[3];
69     reg16 rate_counter_period[3];
70     reg16 exponential_counter[3];
71     reg16 exponential_counter_period[3];
72     reg8 envelope_counter[3];
73     EnvelopeGenerator::State envelope_state[3];
74     bool hold_zero[3];
75   };
76 
77   State read_state();
78   void write_state(const State& state);
79 
80   // 16-bit input (EXT IN).
81   void input(int sample);
82 
83   // 16-bit output (AUDIO OUT).
84   int output();
85   // n-bit output.
86   int output(int bits);
87 
88 protected:
89   static double I0(double x);
90   RESID_INLINE int clock_fast(cycle_count& delta_t, short* buf, int n,
91 			      int interleave);
92   RESID_INLINE int clock_interpolate(cycle_count& delta_t, short* buf, int n,
93 				     int interleave);
94   RESID_INLINE int clock_resample_interpolate(cycle_count& delta_t, short* buf,
95 					      int n, int interleave);
96   RESID_INLINE int clock_resample_fast(cycle_count& delta_t, short* buf,
97 				       int n, int interleave);
98 
99   Voice voice[3];
100   Filter filter;
101   ExternalFilter extfilt;
102   Potentiometer potx;
103   Potentiometer poty;
104 
105   reg8 bus_value;
106   cycle_count bus_value_ttl;
107 
108   double clock_frequency;
109 
110   // External audio input.
111   int ext_in;
112 
113   // Resampling constants.
114   // The error in interpolated lookup is bounded by 1.234/L^2,
115   // while the error in non-interpolated lookup is bounded by
116   // 0.7854/L + 0.4113/L^2, see
117   // http://www-ccrma.stanford.edu/~jos/resample/Choice_Table_Size.html
118   // For a resolution of 16 bits this yields L >= 285 and L >= 51473,
119   // respectively.
120   static const int FIR_N;
121   static const int FIR_RES_INTERPOLATE;
122   static const int FIR_RES_FAST;
123   static const int FIR_SHIFT;
124   static const int RINGSIZE;
125 
126   // Fixpoint constants (16.16 bits).
127   static const int FIXP_SHIFT;
128   static const int FIXP_MASK;
129 
130   // Sampling variables.
131   sampling_method sampling;
132   cycle_count cycles_per_sample;
133   cycle_count sample_offset;
134   int sample_index;
135   short sample_prev;
136   int fir_N;
137   int fir_RES;
138 
139   // Ring buffer with overflow for contiguous storage of RINGSIZE samples.
140   short* sample;
141 
142   // FIR_RES filter tables (FIR_N*FIR_RES).
143   short* fir;
144 };
145 
146 #endif // not __SID_H__
147