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// AY-3-8910 sound chip emulator
// Game_Music_Emu 0.5.2
#ifndef AY_APU_H
#define AY_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Ay_Apu {
public:
// Set buffer to generate all sound into, or disable sound if NULL
void output( Blip_Buffer* );
// Reset sound chip
void reset();
// Write to register at specified time
enum { reg_count = 16 };
void write( blip_time_t time, int addr, int data );
// Run sound to specified time, end current time frame, then start a new
// time frame at time 0. Time frames have no effect on emulation and each
// can be whatever length is convenient.
void end_frame( blip_time_t length );
// Additional features
// Set sound output of specific oscillator to buffer, where index is
// 0, 1, or 2. If buffer is NULL, the specified oscillator is muted.
enum { osc_count = 3 };
void osc_output( int index, Blip_Buffer* );
// Set overall volume (default is 1.0)
void volume( double );
// Set treble equalization (see documentation)
void treble_eq( blip_eq_t const& );
public:
Ay_Apu();
typedef unsigned char 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 latch;
byte regs [reg_count];
struct {
blip_time_t delay;
blargg_ulong lfsr;
} noise;
struct {
blip_time_t delay;
byte const* wave;
int pos;
byte modes [8] [48]; // values already passed through volume table
} env;
void run_until( blip_time_t );
void write_data_( int addr, int data );
public:
enum { amp_range = 255 };
Blip_Synth<blip_good_quality,1> synth_;
};
inline void Ay_Apu::volume( double v ) { synth_.volume( 0.7 / osc_count / amp_range * v ); }
inline void Ay_Apu::treble_eq( blip_eq_t const& eq ) { synth_.treble_eq( eq ); }
inline void Ay_Apu::write( blip_time_t time, int addr, int data )
{
run_until( time );
write_data_( addr, data );
}
inline void Ay_Apu::osc_output( int i, Blip_Buffer* buf )
{
assert( (unsigned) i < osc_count );
oscs [i].output = buf;
}
inline void Ay_Apu::output( Blip_Buffer* buf )
{
osc_output( 0, buf );
osc_output( 1, buf );
osc_output( 2, buf );
}
inline void Ay_Apu::end_frame( blip_time_t time )
{
if ( time > last_time )
run_until( time );
assert( last_time >= time );
last_time -= time;
}
#endif
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