Sms_Apu.h

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// Sega Master System SN76489 PSG sound chip emulator
 
// Sms_Snd_Emu 0.1.4
#ifndef SMS_APU_H
#define SMS_APU_H
 
#include "Sms_Oscs.h"
 
class Sms_Apu {
public:
        // Set overall volume of all oscillators, where 1.0 is full volume
        void volume( double );
        
        // Set treble equalization
        void treble_eq( const blip_eq_t& );
        
        // Outputs can be assigned to a single buffer for mono output, or to three
        // buffers for stereo output (using Stereo_Buffer to do the mixing).
        
        // Assign all oscillator outputs to specified buffer(s). If buffer
        // is NULL, silences all oscillators.
        void output( Blip_Buffer* mono );
        void output( Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
        
        // Assign single oscillator output to buffer(s). Valid indicies are 0 to 3,
        // which refer to Square 1, Square 2, Square 3, and Noise. If buffer is NULL,
        // silences oscillator.
        enum { osc_count = 4 };
        void osc_output( int index, Blip_Buffer* mono );
        void osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
        
        // Reset oscillators and internal state
        void reset( unsigned noise_feedback = 0, int noise_width = 0 );
        
        // Write GameGear left/right assignment byte
        void write_ggstereo( blip_time_t, int );
        
        // Write to data port
        void write_data( blip_time_t, int );
        
        // Run all oscillators up to specified time, end current frame, then
        // start a new frame at time 0.
        void end_frame( blip_time_t );
 
public:
        Sms_Apu();
        ~Sms_Apu();
private:
        // noncopyable
        Sms_Apu( const Sms_Apu& );
        Sms_Apu& operator = ( const Sms_Apu& );
        
        Sms_Osc*    oscs [osc_count];
        Sms_Square  squares [3];
        Sms_Square::Synth square_synth; // used by squares
        blip_time_t last_time;
        int         latch;
        Sms_Noise   noise;
        unsigned    noise_feedback;
        unsigned    looped_feedback;
        
        void run_until( blip_time_t );
};
 
struct sms_apu_state_t
{
        unsigned char regs [8] [2];
        unsigned char latch;
};
 
inline void Sms_Apu::output( Blip_Buffer* b ) { output( b, b, b ); }
 
inline void Sms_Apu::osc_output( int i, Blip_Buffer* b ) { osc_output( i, b, b, b ); }
 
#endif