233 lines
6 KiB
Text
233 lines
6 KiB
Text
/*! \file resid/sid.h */
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// ---------------------------------------------------------------------------
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// This file is part of reSID, a MOS6581 SID emulator engine.
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// Copyright (C) 2010 Dag Lem <resid@nimrod.no>
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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// ---------------------------------------------------------------------------
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#ifndef RESID_SID_H
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#define RESID_SID_H
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#include "resid-config.h"
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#include "voice.h"
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#include "filter.h"
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#include "extfilt.h"
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#include "pot.h"
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namespace reSID
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{
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class SID
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{
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public:
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SID();
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~SID();
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void set_chip_model(chip_model model);
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void set_voice_mask(reg4 mask);
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void enable_filter(bool enable);
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void adjust_filter_bias(double dac_bias);
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void enable_external_filter(bool enable);
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bool set_sampling_parameters(double clock_freq, sampling_method method,
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double sample_freq, double pass_freq = -1,
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double filter_scale = 0.97);
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void adjust_sampling_frequency(double sample_freq);
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void clock();
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void clock(cycle_count delta_t);
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int clock(cycle_count& delta_t, short* buf, int n, int interleave = 1);
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void reset();
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// Read/write registers.
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reg8 read(reg8 offset);
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void write(reg8 offset, reg8 value);
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// Read/write state.
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class State
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{
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public:
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State();
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char sid_register[0x20];
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reg8 bus_value;
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cycle_count bus_value_ttl;
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cycle_count write_pipeline;
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reg8 write_address;
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reg4 voice_mask;
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reg24 accumulator[3];
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reg24 shift_register[3];
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cycle_count shift_register_reset[3];
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cycle_count shift_pipeline[3];
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reg16 pulse_output[3];
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cycle_count floating_output_ttl[3];
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reg16 rate_counter[3];
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reg16 rate_counter_period[3];
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reg16 exponential_counter[3];
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reg16 exponential_counter_period[3];
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reg8 envelope_counter[3];
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EnvelopeGenerator::State envelope_state[3];
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bool hold_zero[3];
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cycle_count envelope_pipeline[3];
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};
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State read_state();
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void write_state(const State& state);
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// 16-bit input (EXT IN).
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void input(short sample);
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// 16-bit output (AUDIO OUT).
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short output();
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protected:
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static double I0(double x);
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int clock_fast(cycle_count& delta_t, short* buf, int n, int interleave);
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int clock_interpolate(cycle_count& delta_t, short* buf, int n,
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int interleave);
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int clock_resample(cycle_count& delta_t, short* buf, int n, int interleave);
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int clock_resample_fastmem(cycle_count& delta_t, short* buf, int n,
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int interleave);
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void write();
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chip_model sid_model;
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Voice voice[3];
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Filter filter;
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ExternalFilter extfilt;
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Potentiometer potx;
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Potentiometer poty;
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reg8 bus_value;
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cycle_count bus_value_ttl;
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// Pipeline for writes on the MOS8580.
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cycle_count write_pipeline;
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reg8 write_address;
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double clock_frequency;
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enum {
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// Resampling constants.
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// The error in interpolated lookup is bounded by 1.234/L^2,
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// while the error in non-interpolated lookup is bounded by
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// 0.7854/L + 0.4113/L^2, see
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// http://www-ccrma.stanford.edu/~jos/resample/Choice_Table_Size.html
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// For a resolution of 16 bits this yields L >= 285 and L >= 51473,
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// respectively.
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FIR_N = 125,
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FIR_RES = 285,
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FIR_RES_FASTMEM = 51473,
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FIR_SHIFT = 15,
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RINGSIZE = 1 << 14,
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RINGMASK = RINGSIZE - 1,
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// Fixed point constants (16.16 bits).
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FIXP_SHIFT = 16,
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FIXP_MASK = 0xffff
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};
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// Sampling variables.
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sampling_method sampling;
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cycle_count cycles_per_sample;
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cycle_count sample_offset;
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int sample_index;
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short sample_prev, sample_now;
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int fir_N;
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int fir_RES;
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double fir_beta;
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double fir_f_cycles_per_sample;
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double fir_filter_scale;
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// Ring buffer with overflow for contiguous storage of RINGSIZE samples.
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short* sample;
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// FIR_RES filter tables (FIR_N*FIR_RES).
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short* fir;
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};
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// ----------------------------------------------------------------------------
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// Inline functions.
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// The following functions are defined inline because they are called every
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// time a sample is calculated.
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// ----------------------------------------------------------------------------
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#if RESID_INLINING || defined(RESID_SID_CC)
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// ----------------------------------------------------------------------------
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// Read 16-bit sample from audio output.
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// ----------------------------------------------------------------------------
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RESID_INLINE
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short SID::output()
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{
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return extfilt.output();
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}
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// ----------------------------------------------------------------------------
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// SID clocking - 1 cycle.
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// ----------------------------------------------------------------------------
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RESID_INLINE
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void SID::clock()
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{
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int i;
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// Clock amplitude modulators.
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for (i = 0; i < 3; i++) {
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voice[i].envelope.clock();
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}
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// Clock oscillators.
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for (i = 0; i < 3; i++) {
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voice[i].wave.clock();
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}
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// Synchronize oscillators.
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for (i = 0; i < 3; i++) {
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voice[i].wave.synchronize();
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}
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// Calculate waveform output.
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for (i = 0; i < 3; i++) {
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voice[i].wave.set_waveform_output();
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}
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// Clock filter.
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filter.clock(voice[0].output(), voice[1].output(), voice[2].output());
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// Clock external filter.
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extfilt.clock(filter.output());
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// Pipelined writes on the MOS8580.
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if (unlikely(write_pipeline)) {
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write();
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}
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// Age bus value.
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if (unlikely(!--bus_value_ttl)) {
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bus_value = 0;
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}
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}
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#endif // RESID_INLINING || defined(RESID_SID_CC)
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} // namespace reSID
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#endif // not RESID_SID_H
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