Nes_Namco_Apu.h

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// Namco 106 sound chip emulator
 
// Nes_Snd_Emu 0.1.8
#ifndef NES_NAMCO_APU_H
#define NES_NAMCO_APU_H
 
#include "blargg_common.h"
#include "Blip_Buffer.h"
 
struct namco_state_t;
 
class Nes_Namco_Apu {
public:
        // See Nes_Apu.h for reference.
        void volume( double );
        void treble_eq( const blip_eq_t& );
        void output( Blip_Buffer* );
        enum { osc_count = 8 };
        void osc_output( int index, Blip_Buffer* );
        void reset();
        void end_frame( blip_time_t );
        
        // Read/write data register is at 0x4800
        enum { data_reg_addr = 0x4800 };
        void write_data( blip_time_t, int );
        int read_data();
        
        // Write-only address register is at 0xF800
        enum { addr_reg_addr = 0xF800 };
        void write_addr( int );
        
        // to do: implement save/restore
        void save_state( namco_state_t* out ) const;
        void load_state( namco_state_t const& );
        
public:
        Nes_Namco_Apu();
        BLARGG_DISABLE_NOTHROW
private:
        // noncopyable
        Nes_Namco_Apu( const Nes_Namco_Apu& );
        Nes_Namco_Apu& operator = ( const Nes_Namco_Apu& );
        
        struct Namco_Osc {
                blargg_long delay;
                Blip_Buffer* output;
                short last_amp;
                short wave_pos;
        };
        
        Namco_Osc oscs [osc_count];
        
        blip_time_t last_time;
        int addr_reg;
        
        enum { reg_count = 0x80 };
        uint8_t reg [reg_count];
        Blip_Synth<blip_good_quality,15> synth;
        
        uint8_t& access();
        void run_until( blip_time_t );
};
/*
struct namco_state_t
{
        uint8_t regs [0x80];
        uint8_t addr;
        uint8_t unused;
        uint8_t positions [8];
        uint32_t delays [8];
};
*/
 
inline uint8_t& Nes_Namco_Apu::access()
{
        int addr = addr_reg & 0x7F;
        if ( addr_reg & 0x80 )
                addr_reg = (addr + 1) | 0x80;
        return reg [addr];
}
 
inline void Nes_Namco_Apu::volume( double v ) { synth.volume( 0.10 / osc_count * v ); }
 
inline void Nes_Namco_Apu::treble_eq( const blip_eq_t& eq ) { synth.treble_eq( eq ); }
 
inline void Nes_Namco_Apu::write_addr( int v ) { addr_reg = v; }
 
inline int Nes_Namco_Apu::read_data() { return access(); }
 
inline void Nes_Namco_Apu::osc_output( int i, Blip_Buffer* buf )
{
        assert( (unsigned) i < osc_count );
        oscs [i].output = buf;
}
 
inline void Nes_Namco_Apu::write_data( blip_time_t time, int data )
{
        run_until( time );
        access() = data;
}
 
#endif