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// Atari POKEY sound chip emulator
// Game_Music_Emu 0.5.2
#ifndef SAP_APU_H
#define SAP_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Sap_Apu_Impl;
class Sap_Apu {
public:
enum { osc_count = 4 };
void osc_output( int index, Blip_Buffer* );
void reset( Sap_Apu_Impl* );
enum { start_addr = 0xD200 };
enum { end_addr = 0xD209 };
void write_data( blip_time_t, unsigned addr, int data );
void end_frame( blip_time_t );
public:
Sap_Apu();
private:
struct osc_t
{
unsigned char regs [2];
unsigned char phase;
unsigned char invert;
int last_amp;
blip_time_t delay;
blip_time_t period; // always recalculated before use; here for convenience
Blip_Buffer* output;
};
osc_t oscs [osc_count];
Sap_Apu_Impl* impl;
blip_time_t last_time;
int poly5_pos;
int poly4_pos;
int polym_pos;
int control;
void calc_periods();
void run_until( blip_time_t );
enum { poly4_len = (1L << 4) - 1 };
enum { poly9_len = (1L << 9) - 1 };
enum { poly17_len = (1L << 17) - 1 };
friend class Sap_Apu_Impl;
};
// Common tables and Blip_Synth that can be shared among multiple Sap_Apu objects
class Sap_Apu_Impl {
public:
Blip_Synth<blip_good_quality,1> synth;
Sap_Apu_Impl();
void volume( double d ) { synth.volume( 1.0 / Sap_Apu::osc_count / 30 * d ); }
private:
typedef unsigned char byte;
byte poly4 [Sap_Apu::poly4_len / 8 + 1];
byte poly9 [Sap_Apu::poly9_len / 8 + 1];
byte poly17 [Sap_Apu::poly17_len / 8 + 1];
friend class Sap_Apu;
};
inline void Sap_Apu::osc_output( int i, Blip_Buffer* b )
{
assert( (unsigned) i < osc_count );
oscs [i].output = b;
}
#endif
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