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// AY-3-8910 sound chip emulator
// Game_Music_Emu 0.6-pre
#ifndef AY_APU_H
#define AY_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Ay_Apu {
public:
// Basics
// Sets buffer to generate sound into, or 0 to mute.
void set_output( Blip_Buffer* );
// Writes to address register
void write_addr( int data ) { addr_ = data & 0x0F; }
// Emulates to time t, then writes to current data register
void write_data( blip_time_t t, int data ) { run_until( t ); write_data_( addr_, data ); }
// Emulates to time t, then subtracts t from the current time.
// OK if previous write call had time slightly after t.
void end_frame( blip_time_t t );
// More features
// Reads from current data register
int read();
// Resets sound chip
void reset();
// Number of registers
enum { reg_count = 16 };
// Same as set_output(), but for a particular channel
enum { osc_count = 3 };
void set_output( int chan, Blip_Buffer* );
// Sets overall volume, where 1.0 is normal
void volume( double v ) { synth_.volume( 0.7/osc_count/amp_range * v ); }
// Sets treble equalization
void treble_eq( blip_eq_t const& eq ) { synth_.treble_eq( eq ); }
private:
// noncopyable
Ay_Apu( const Ay_Apu& );
Ay_Apu& operator = ( const Ay_Apu& );
// Implementation
public:
Ay_Apu();
BLARGG_DISABLE_NOTHROW
typedef BOOST::uint8_t byte;
private:
struct osc_t
{
blip_time_t period;
blip_time_t delay;
short last_amp;
short phase;
Blip_Buffer* output;
} oscs [osc_count];
blip_time_t last_time;
byte addr_;
byte regs [reg_count];
blip_time_t noise_delay;
unsigned noise_lfsr;
blip_time_t env_delay;
byte const* env_wave;
int env_pos;
byte env_modes [8] [48]; // values already passed through volume table
void write_data_( int addr, int data );
void run_until( blip_time_t );
public:
enum { amp_range = 255 };
Blip_Synth_Norm synth_; // used by Ay_Core for beeper sound
};
inline void Ay_Apu::set_output( int i, Blip_Buffer* out )
{
assert( (unsigned) i < osc_count );
oscs [i].output = out;
}
inline void Ay_Apu::end_frame( blip_time_t time )
{
if ( time > last_time )
run_until( time );
last_time -= time;
assert( last_time >= 0 );
}
#endif
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