257 lines
6.9 KiB
C++
257 lines
6.9 KiB
C++
/*
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* Copyright (C) 2002-2010 The DOSBox Team
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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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#include "adlib.h"
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#include "dosbox.h"
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//Use 8 handlers based on a small logatirmic wavetabe and an exponential table for volume
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#define WAVE_HANDLER 10
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//Use a logarithmic wavetable with an exponential table for volume
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#define WAVE_TABLELOG 11
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//Use a linear wavetable with a multiply table for volume
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#define WAVE_TABLEMUL 12
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//Select the type of wave generator routine
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#define DBOPL_WAVE WAVE_TABLEMUL
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namespace DBOPL {
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struct Chip;
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struct Operator;
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struct Channel;
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#if (DBOPL_WAVE == WAVE_HANDLER)
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typedef Bits ( DB_FASTCALL *WaveHandler) ( Bitu i, Bitu volume );
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#endif
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typedef Bits ( DBOPL::Operator::*VolumeHandler) ( );
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typedef Channel* ( DBOPL::Channel::*SynthHandler) ( Chip* chip, Bit32u samples, Bit32s* output );
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//Different synth modes that can generate blocks of data
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typedef enum {
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sm2AM,
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sm2FM,
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sm3AM,
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sm3FM,
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sm4Start,
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sm3FMFM,
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sm3AMFM,
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sm3FMAM,
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sm3AMAM,
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sm6Start,
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sm2Percussion,
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sm3Percussion,
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} SynthMode;
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//Shifts for the values contained in chandata variable
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enum {
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SHIFT_KSLBASE = 16,
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SHIFT_KEYCODE = 24,
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};
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struct Operator {
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public:
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//Masks for operator 20 values
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enum {
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MASK_KSR = 0x10,
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MASK_SUSTAIN = 0x20,
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MASK_VIBRATO = 0x40,
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MASK_TREMOLO = 0x80,
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};
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typedef enum {
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OFF,
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RELEASE,
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SUSTAIN,
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DECAY,
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ATTACK,
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} State;
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VolumeHandler volHandler;
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#if (DBOPL_WAVE == WAVE_HANDLER)
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WaveHandler waveHandler; //Routine that generate a wave
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#else
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Bit16s* waveBase;
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Bit32u waveMask;
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Bit32u waveStart;
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#endif
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Bit32u waveIndex; //WAVE_BITS shifted counter of the frequency index
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Bit32u waveAdd; //The base frequency without vibrato
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Bit32u waveCurrent; //waveAdd + vibratao
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Bit32u chanData; //Frequency/octave and derived data coming from whatever channel controls this
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Bit32u freqMul; //Scale channel frequency with this, TODO maybe remove?
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Bit32u vibrato; //Scaled up vibrato strength
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Bit32s sustainLevel; //When stopping at sustain level stop here
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Bit32s totalLevel; //totalLevel is added to every generated volume
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Bit32u currentLevel; //totalLevel + tremolo
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Bit32s volume; //The currently active volume
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Bit32u attackAdd; //Timers for the different states of the envelope
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Bit32u decayAdd;
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Bit32u releaseAdd;
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Bit32u rateIndex; //Current position of the evenlope
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Bit8u rateZero; //Bits for the different states of the envelope having no changes
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Bit8u keyOn; //Bitmask of different values that can generate keyon
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//Registers, also used to check for changes
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Bit8u reg20, reg40, reg60, reg80, regE0;
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//Active part of the envelope we're in
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Bit8u state;
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//0xff when tremolo is enabled
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Bit8u tremoloMask;
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//Strength of the vibrato
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Bit8u vibStrength;
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//Keep track of the calculated KSR so we can check for changes
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Bit8u ksr;
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private:
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void SetState( Bit8u s );
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void UpdateAttack( const Chip* chip );
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void UpdateRelease( const Chip* chip );
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void UpdateDecay( const Chip* chip );
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public:
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void UpdateAttenuation();
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void UpdateRates( const Chip* chip );
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void UpdateFrequency( );
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void Write20( const Chip* chip, Bit8u val );
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void Write40( const Chip* chip, Bit8u val );
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void Write60( const Chip* chip, Bit8u val );
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void Write80( const Chip* chip, Bit8u val );
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void WriteE0( const Chip* chip, Bit8u val );
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bool Silent() const;
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void Prepare( const Chip* chip );
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void KeyOn( Bit8u mask);
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void KeyOff( Bit8u mask);
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template< State state>
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Bits TemplateVolume( );
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Bit32s RateForward( Bit32u add );
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Bitu ForwardWave();
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Bitu ForwardVolume();
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Bits GetSample( Bits modulation );
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Bits GetWave( Bitu index, Bitu vol );
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public:
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Operator();
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};
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struct Channel {
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Operator op[2];
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inline Operator* Op( Bitu index ) {
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return &( ( this + (index >> 1) )->op[ index & 1 ]);
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}
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SynthHandler synthHandler;
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Bit32u chanData; //Frequency/octave and derived values
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Bit32s old[2]; //Old data for feedback
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Bit8u feedback; //Feedback shift
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Bit8u regB0; //Register values to check for changes
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Bit8u regC0;
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//This should correspond with reg104, bit 6 indicates a Percussion channel, bit 7 indicates a silent channel
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Bit8u fourMask;
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Bit8s maskLeft; //Sign extended values for both channel's panning
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Bit8s maskRight;
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//Forward the channel data to the operators of the channel
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void SetChanData( const Chip* chip, Bit32u data );
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//Change in the chandata, check for new values and if we have to forward to operators
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void UpdateFrequency( const Chip* chip, Bit8u fourOp );
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void WriteA0( const Chip* chip, Bit8u val );
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void WriteB0( const Chip* chip, Bit8u val );
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void WriteC0( const Chip* chip, Bit8u val );
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void ResetC0( const Chip* chip );
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//call this for the first channel
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template< bool opl3Mode >
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void GeneratePercussion( Chip* chip, Bit32s* output );
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//Generate blocks of data in specific modes
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template<SynthMode mode>
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Channel* BlockTemplate( Chip* chip, Bit32u samples, Bit32s* output );
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Channel();
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};
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struct Chip {
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//This is used as the base counter for vibrato and tremolo
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Bit32u lfoCounter;
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Bit32u lfoAdd;
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Bit32u noiseCounter;
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Bit32u noiseAdd;
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Bit32u noiseValue;
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//Frequency scales for the different multiplications
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Bit32u freqMul[16];
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//Rates for decay and release for rate of this chip
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Bit32u linearRates[76];
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//Best match attack rates for the rate of this chip
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Bit32u attackRates[76];
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//18 channels with 2 operators each
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Channel chan[18];
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Bit8u reg104;
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Bit8u reg08;
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Bit8u reg04;
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Bit8u regBD;
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Bit8u vibratoIndex;
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Bit8u tremoloIndex;
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Bit8s vibratoSign;
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Bit8u vibratoShift;
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Bit8u tremoloValue;
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Bit8u vibratoStrength;
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Bit8u tremoloStrength;
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//Mask for allowed wave forms
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Bit8u waveFormMask;
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//0 or -1 when enabled
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Bit8s opl3Active;
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//Return the maximum amount of samples before and LFO change
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Bit32u ForwardLFO( Bit32u samples );
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Bit32u ForwardNoise();
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void WriteBD( Bit8u val );
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void WriteReg(Bit32u reg, Bit8u val );
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Bit32u WriteAddr( Bit32u port, Bit8u val );
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void GenerateBlock2( Bitu samples, Bit32s* output );
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void GenerateBlock3( Bitu samples, Bit32s* output );
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void Generate( Bitu samples, Bit32s *buffer );
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void Setup( Bit32u r );
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Chip();
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};
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struct Handler : public Adlib::Handler {
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DBOPL::Chip chip;
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virtual Bit32u WriteAddr( Bit32u port, Bit8u val );
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virtual void WriteReg( Bit32u addr, Bit8u val );
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virtual void Generate( Bitu samples, Bit32s *buffer );
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virtual void Init( Bitu rate );
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};
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}; //Namespace
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