2
0
Fork 0
OPL/Source/dbopl.h
2013-09-04 21:37:36 +08:00

257 lines
6.9 KiB
C++

/*
* Copyright (C) 2002-2010 The DOSBox Team
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "adlib.h"
#include "dosbox.h"
//Use 8 handlers based on a small logatirmic wavetabe and an exponential table for volume
#define WAVE_HANDLER 10
//Use a logarithmic wavetable with an exponential table for volume
#define WAVE_TABLELOG 11
//Use a linear wavetable with a multiply table for volume
#define WAVE_TABLEMUL 12
//Select the type of wave generator routine
#define DBOPL_WAVE WAVE_TABLEMUL
namespace DBOPL {
struct Chip;
struct Operator;
struct Channel;
#if (DBOPL_WAVE == WAVE_HANDLER)
typedef Bits ( DB_FASTCALL *WaveHandler) ( Bitu i, Bitu volume );
#endif
typedef Bits ( DBOPL::Operator::*VolumeHandler) ( );
typedef Channel* ( DBOPL::Channel::*SynthHandler) ( Chip* chip, Bit32u samples, Bit32s* output );
//Different synth modes that can generate blocks of data
typedef enum {
sm2AM,
sm2FM,
sm3AM,
sm3FM,
sm4Start,
sm3FMFM,
sm3AMFM,
sm3FMAM,
sm3AMAM,
sm6Start,
sm2Percussion,
sm3Percussion,
} SynthMode;
//Shifts for the values contained in chandata variable
enum {
SHIFT_KSLBASE = 16,
SHIFT_KEYCODE = 24,
};
struct Operator {
public:
//Masks for operator 20 values
enum {
MASK_KSR = 0x10,
MASK_SUSTAIN = 0x20,
MASK_VIBRATO = 0x40,
MASK_TREMOLO = 0x80,
};
typedef enum {
OFF,
RELEASE,
SUSTAIN,
DECAY,
ATTACK,
} State;
VolumeHandler volHandler;
#if (DBOPL_WAVE == WAVE_HANDLER)
WaveHandler waveHandler; //Routine that generate a wave
#else
Bit16s* waveBase;
Bit32u waveMask;
Bit32u waveStart;
#endif
Bit32u waveIndex; //WAVE_BITS shifted counter of the frequency index
Bit32u waveAdd; //The base frequency without vibrato
Bit32u waveCurrent; //waveAdd + vibratao
Bit32u chanData; //Frequency/octave and derived data coming from whatever channel controls this
Bit32u freqMul; //Scale channel frequency with this, TODO maybe remove?
Bit32u vibrato; //Scaled up vibrato strength
Bit32s sustainLevel; //When stopping at sustain level stop here
Bit32s totalLevel; //totalLevel is added to every generated volume
Bit32u currentLevel; //totalLevel + tremolo
Bit32s volume; //The currently active volume
Bit32u attackAdd; //Timers for the different states of the envelope
Bit32u decayAdd;
Bit32u releaseAdd;
Bit32u rateIndex; //Current position of the evenlope
Bit8u rateZero; //Bits for the different states of the envelope having no changes
Bit8u keyOn; //Bitmask of different values that can generate keyon
//Registers, also used to check for changes
Bit8u reg20, reg40, reg60, reg80, regE0;
//Active part of the envelope we're in
Bit8u state;
//0xff when tremolo is enabled
Bit8u tremoloMask;
//Strength of the vibrato
Bit8u vibStrength;
//Keep track of the calculated KSR so we can check for changes
Bit8u ksr;
private:
void SetState( Bit8u s );
void UpdateAttack( const Chip* chip );
void UpdateRelease( const Chip* chip );
void UpdateDecay( const Chip* chip );
public:
void UpdateAttenuation();
void UpdateRates( const Chip* chip );
void UpdateFrequency( );
void Write20( const Chip* chip, Bit8u val );
void Write40( const Chip* chip, Bit8u val );
void Write60( const Chip* chip, Bit8u val );
void Write80( const Chip* chip, Bit8u val );
void WriteE0( const Chip* chip, Bit8u val );
bool Silent() const;
void Prepare( const Chip* chip );
void KeyOn( Bit8u mask);
void KeyOff( Bit8u mask);
template< State state>
Bits TemplateVolume( );
Bit32s RateForward( Bit32u add );
Bitu ForwardWave();
Bitu ForwardVolume();
Bits GetSample( Bits modulation );
Bits GetWave( Bitu index, Bitu vol );
public:
Operator();
};
struct Channel {
Operator op[2];
inline Operator* Op( Bitu index ) {
return &( ( this + (index >> 1) )->op[ index & 1 ]);
}
SynthHandler synthHandler;
Bit32u chanData; //Frequency/octave and derived values
Bit32s old[2]; //Old data for feedback
Bit8u feedback; //Feedback shift
Bit8u regB0; //Register values to check for changes
Bit8u regC0;
//This should correspond with reg104, bit 6 indicates a Percussion channel, bit 7 indicates a silent channel
Bit8u fourMask;
Bit8s maskLeft; //Sign extended values for both channel's panning
Bit8s maskRight;
//Forward the channel data to the operators of the channel
void SetChanData( const Chip* chip, Bit32u data );
//Change in the chandata, check for new values and if we have to forward to operators
void UpdateFrequency( const Chip* chip, Bit8u fourOp );
void WriteA0( const Chip* chip, Bit8u val );
void WriteB0( const Chip* chip, Bit8u val );
void WriteC0( const Chip* chip, Bit8u val );
void ResetC0( const Chip* chip );
//call this for the first channel
template< bool opl3Mode >
void GeneratePercussion( Chip* chip, Bit32s* output );
//Generate blocks of data in specific modes
template<SynthMode mode>
Channel* BlockTemplate( Chip* chip, Bit32u samples, Bit32s* output );
Channel();
};
struct Chip {
//This is used as the base counter for vibrato and tremolo
Bit32u lfoCounter;
Bit32u lfoAdd;
Bit32u noiseCounter;
Bit32u noiseAdd;
Bit32u noiseValue;
//Frequency scales for the different multiplications
Bit32u freqMul[16];
//Rates for decay and release for rate of this chip
Bit32u linearRates[76];
//Best match attack rates for the rate of this chip
Bit32u attackRates[76];
//18 channels with 2 operators each
Channel chan[18];
Bit8u reg104;
Bit8u reg08;
Bit8u reg04;
Bit8u regBD;
Bit8u vibratoIndex;
Bit8u tremoloIndex;
Bit8s vibratoSign;
Bit8u vibratoShift;
Bit8u tremoloValue;
Bit8u vibratoStrength;
Bit8u tremoloStrength;
//Mask for allowed wave forms
Bit8u waveFormMask;
//0 or -1 when enabled
Bit8s opl3Active;
//Return the maximum amount of samples before and LFO change
Bit32u ForwardLFO( Bit32u samples );
Bit32u ForwardNoise();
void WriteBD( Bit8u val );
void WriteReg(Bit32u reg, Bit8u val );
Bit32u WriteAddr( Bit32u port, Bit8u val );
void GenerateBlock2( Bitu samples, Bit32s* output );
void GenerateBlock3( Bitu samples, Bit32s* output );
void Generate( Bitu samples, Bit32s *buffer );
void Setup( Bit32u r );
Chip();
};
struct Handler : public Adlib::Handler {
DBOPL::Chip chip;
virtual Bit32u WriteAddr( Bit32u port, Bit8u val );
virtual void WriteReg( Bit32u addr, Bit8u val );
virtual void Generate( Bitu samples, Bit32s *buffer );
virtual void Init( Bitu rate );
};
}; //Namespace