mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-23 02:11:38 +00:00
39846310d7
svn-id: r51671
349 lines
7.1 KiB
C++
349 lines
7.1 KiB
C++
/* ScummVM - Graphic Adventure Engine
|
|
*
|
|
* ScummVM is the legal property of its developers, whose names
|
|
* are too numerous to list here. Please refer to the COPYRIGHT
|
|
* file distributed with this source distribution.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*
|
|
* $URL$
|
|
* $Id$
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* This file is based on reSID, a MOS6581 SID emulator engine.
|
|
* Copyright (C) 2004 Dag Lem <resid@nimrod.no>
|
|
*/
|
|
|
|
#ifndef __SID_H__
|
|
#define __SID_H__
|
|
|
|
// Inlining on/off.
|
|
#define RESID_INLINE inline
|
|
|
|
namespace Resid {
|
|
|
|
// We could have used the smallest possible data type for each SID register,
|
|
// however this would give a slower engine because of data type conversions.
|
|
// An int is assumed to be at least 32 bits (necessary in the types reg24,
|
|
// cycle_count, and sound_sample). GNU does not support 16-bit machines
|
|
// (GNU Coding Standards: Portability between CPUs), so this should be
|
|
// a valid assumption.
|
|
|
|
typedef unsigned int reg4;
|
|
typedef unsigned int reg8;
|
|
typedef unsigned int reg12;
|
|
typedef unsigned int reg16;
|
|
typedef unsigned int reg24;
|
|
|
|
typedef int cycle_count;
|
|
typedef int sound_sample;
|
|
typedef sound_sample fc_point[2];
|
|
|
|
|
|
class WaveformGenerator {
|
|
public:
|
|
WaveformGenerator();
|
|
|
|
void set_sync_source(WaveformGenerator*);
|
|
|
|
void clock(cycle_count delta_t);
|
|
void synchronize();
|
|
void reset();
|
|
|
|
void writeFREQ_LO(reg8);
|
|
void writeFREQ_HI(reg8);
|
|
void writePW_LO(reg8);
|
|
void writePW_HI(reg8);
|
|
void writeCONTROL_REG(reg8);
|
|
reg8 readOSC();
|
|
|
|
// 12-bit waveform output.
|
|
reg12 output();
|
|
|
|
protected:
|
|
const WaveformGenerator* sync_source;
|
|
WaveformGenerator* sync_dest;
|
|
|
|
// Tell whether the accumulator MSB was set high on this cycle.
|
|
bool msb_rising;
|
|
|
|
reg24 accumulator;
|
|
reg24 shift_register;
|
|
|
|
// Fout = (Fn*Fclk/16777216)Hz
|
|
reg16 freq;
|
|
// PWout = (PWn/40.95)%
|
|
reg12 pw;
|
|
|
|
// The control register right-shifted 4 bits; used for output function
|
|
// table lookup.
|
|
reg8 waveform;
|
|
|
|
// The remaining control register bits.
|
|
reg8 test;
|
|
reg8 ring_mod;
|
|
reg8 sync;
|
|
// The gate bit is handled by the EnvelopeGenerator.
|
|
|
|
// 16 possible combinations of waveforms.
|
|
reg12 output____();
|
|
reg12 output___T();
|
|
reg12 output__S_();
|
|
reg12 output__ST();
|
|
reg12 output_P__();
|
|
reg12 output_P_T();
|
|
reg12 output_PS_();
|
|
reg12 output_PST();
|
|
reg12 outputN___();
|
|
reg12 outputN__T();
|
|
reg12 outputN_S_();
|
|
reg12 outputN_ST();
|
|
reg12 outputNP__();
|
|
reg12 outputNP_T();
|
|
reg12 outputNPS_();
|
|
reg12 outputNPST();
|
|
|
|
// Sample data for combinations of waveforms.
|
|
static const reg8 wave6581__ST[];
|
|
static const reg8 wave6581_P_T[];
|
|
static const reg8 wave6581_PS_[];
|
|
static const reg8 wave6581_PST[];
|
|
|
|
friend class Voice;
|
|
friend class SID;
|
|
};
|
|
|
|
class Filter {
|
|
public:
|
|
Filter();
|
|
|
|
void enable_filter(bool enable);
|
|
|
|
void clock(cycle_count delta_t,
|
|
sound_sample voice1, sound_sample voice2, sound_sample voice3);
|
|
void reset();
|
|
|
|
// Write registers.
|
|
void writeFC_LO(reg8);
|
|
void writeFC_HI(reg8);
|
|
void writeRES_FILT(reg8);
|
|
void writeMODE_VOL(reg8);
|
|
|
|
// SID audio output (16 bits).
|
|
sound_sample output();
|
|
|
|
protected:
|
|
void set_w0();
|
|
void set_Q();
|
|
|
|
// Filter enabled.
|
|
bool enabled;
|
|
|
|
// Filter cutoff frequency.
|
|
reg12 fc;
|
|
|
|
// Filter resonance.
|
|
reg8 res;
|
|
|
|
// Selects which inputs to route through filter.
|
|
reg8 filt;
|
|
|
|
// Switch voice 3 off.
|
|
reg8 voice3off;
|
|
|
|
// Highpass, bandpass, and lowpass filter modes.
|
|
reg8 hp_bp_lp;
|
|
|
|
// Output master volume.
|
|
reg4 vol;
|
|
|
|
// Mixer DC offset.
|
|
sound_sample mixer_DC;
|
|
|
|
// State of filter.
|
|
sound_sample Vhp; // highpass
|
|
sound_sample Vbp; // bandpass
|
|
sound_sample Vlp; // lowpass
|
|
sound_sample Vnf; // not filtered
|
|
|
|
// Cutoff frequency, resonance.
|
|
sound_sample w0, w0_ceil_1, w0_ceil_dt;
|
|
sound_sample _1024_div_Q;
|
|
|
|
// Cutoff frequency tables.
|
|
// FC is an 11 bit register.
|
|
sound_sample f0_6581[2048];
|
|
sound_sample* f0;
|
|
static fc_point f0_points_6581[];
|
|
fc_point* f0_points;
|
|
int f0_count;
|
|
|
|
friend class SID;
|
|
};
|
|
|
|
class EnvelopeGenerator {
|
|
public:
|
|
EnvelopeGenerator();
|
|
|
|
enum State { ATTACK, DECAY_SUSTAIN, RELEASE };
|
|
|
|
void clock(cycle_count delta_t);
|
|
void reset();
|
|
|
|
void writeCONTROL_REG(reg8);
|
|
void writeATTACK_DECAY(reg8);
|
|
void writeSUSTAIN_RELEASE(reg8);
|
|
reg8 readENV();
|
|
|
|
// 8-bit envelope output.
|
|
reg8 output();
|
|
|
|
protected:
|
|
reg16 rate_counter;
|
|
reg16 rate_period;
|
|
reg8 exponential_counter;
|
|
reg8 exponential_counter_period;
|
|
reg8 envelope_counter;
|
|
bool hold_zero;
|
|
|
|
reg4 attack;
|
|
reg4 decay;
|
|
reg4 sustain;
|
|
reg4 release;
|
|
|
|
reg8 gate;
|
|
|
|
State state;
|
|
|
|
// Lookup table to convert from attack, decay, or release value to rate
|
|
// counter period.
|
|
static reg16 rate_counter_period[];
|
|
|
|
// The 16 selectable sustain levels.
|
|
static reg8 sustain_level[];
|
|
|
|
friend class SID;
|
|
};
|
|
|
|
class ExternalFilter {
|
|
public:
|
|
ExternalFilter();
|
|
|
|
void enable_filter(bool enable);
|
|
void set_sampling_parameter(double pass_freq);
|
|
|
|
void clock(cycle_count delta_t, sound_sample Vi);
|
|
void reset();
|
|
|
|
// Audio output (20 bits).
|
|
sound_sample output();
|
|
|
|
protected:
|
|
// Filter enabled.
|
|
bool enabled;
|
|
|
|
// Maximum mixer DC offset.
|
|
sound_sample mixer_DC;
|
|
|
|
// State of filters.
|
|
sound_sample Vlp; // lowpass
|
|
sound_sample Vhp; // highpass
|
|
sound_sample Vo;
|
|
|
|
// Cutoff frequencies.
|
|
sound_sample w0lp;
|
|
sound_sample w0hp;
|
|
|
|
friend class SID;
|
|
};
|
|
|
|
class Voice {
|
|
public:
|
|
Voice();
|
|
|
|
void set_sync_source(Voice*);
|
|
void reset();
|
|
|
|
void writeCONTROL_REG(reg8);
|
|
|
|
// Amplitude modulated waveform output.
|
|
// Range [-2048*255, 2047*255].
|
|
sound_sample output() {
|
|
// Multiply oscillator output with envelope output.
|
|
return (wave.output() - wave_zero)*envelope.output() + voice_DC;
|
|
}
|
|
|
|
protected:
|
|
WaveformGenerator wave;
|
|
EnvelopeGenerator envelope;
|
|
|
|
// Waveform D/A zero level.
|
|
sound_sample wave_zero;
|
|
|
|
// Multiplying D/A DC offset.
|
|
sound_sample voice_DC;
|
|
|
|
friend class SID;
|
|
};
|
|
|
|
|
|
class SID {
|
|
public:
|
|
SID();
|
|
~SID();
|
|
|
|
void enable_filter(bool enable);
|
|
void enable_external_filter(bool enable);
|
|
bool set_sampling_parameters(double clock_freq,
|
|
double sample_freq, double pass_freq = -1,
|
|
double filter_scale = 0.97);
|
|
|
|
void clock(cycle_count delta_t);
|
|
int clock(cycle_count& delta_t, short* buf, int n, int interleave = 1);
|
|
void reset();
|
|
|
|
// Read/write registers.
|
|
reg8 read(reg8 offset);
|
|
void write(reg8 offset, reg8 value);
|
|
|
|
// 16-bit output (AUDIO OUT).
|
|
int output();
|
|
|
|
protected:
|
|
Voice voice[3];
|
|
Filter filter;
|
|
ExternalFilter extfilt;
|
|
|
|
reg8 bus_value;
|
|
cycle_count bus_value_ttl;
|
|
|
|
double clock_frequency;
|
|
|
|
// Fixpoint constants.
|
|
static const int FIXP_SHIFT;
|
|
static const int FIXP_MASK;
|
|
|
|
// Sampling variables.
|
|
cycle_count cycles_per_sample;
|
|
cycle_count sample_offset;
|
|
short sample_prev;
|
|
};
|
|
|
|
}
|
|
|
|
#endif // not __SID_H__
|