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// Konami VRC6 sound chip emulator
// Nes_Snd_Emu 0.2.0-pre
#ifndef NES_VRC6_APU_H
#define NES_VRC6_APU_H
#include "blargg_common.h"
#include "blip_buffer.h"
enum { vrc6_osc_count = 3 };
enum { vrc6_reg_count = 3 };
enum { vrc6_base_addr = 0x9000 };
enum { vrc6_addr_step = 0x1000 };
struct Vrc6_Osc
{
uint8_t regs [3];
struct Blip_Buffer* output;
int delay;
int last_amp;
int phase;
int amp; // only used by saw
};
static inline int Vrc6_osc_period( struct Vrc6_Osc* this )
{
return (this->regs [2] & 0x0F) * 0x100 + this->regs [1] + 1;
}
struct Nes_Vrc6_Apu {
struct Vrc6_Osc oscs [vrc6_osc_count];
blip_time_t last_time;
struct Blip_Synth saw_synth;
struct Blip_Synth square_synth;
};
// See Nes_Apu.h for reference
void Vrc6_init( struct Nes_Vrc6_Apu* this );
void Vrc6_reset( struct Nes_Vrc6_Apu* this );
void Vrc6_output( struct Nes_Vrc6_Apu* this, struct Blip_Buffer* );
void Vrc6_end_frame( struct Nes_Vrc6_Apu* this, blip_time_t );
// Oscillator 0 write-only registers are at $9000-$9002
// Oscillator 1 write-only registers are at $A000-$A002
// Oscillator 2 write-only registers are at $B000-$B002
void Vrc6_write_osc( struct Nes_Vrc6_Apu* this, blip_time_t, int osc, int reg, int data );
static inline void Vrc6_osc_output( struct Nes_Vrc6_Apu* this, int i, struct Blip_Buffer* buf )
{
assert( (unsigned) i < vrc6_osc_count );
this->oscs [i].output = buf;
}
static inline void Vrc6_volume( struct Nes_Vrc6_Apu* this, int v )
{
long long const factor = (long long)(FP_ONE_VOLUME * 0.0967 * 2);
Synth_volume( &this->saw_synth, (int)(v * factor / 31 / FP_ONE_VOLUME) );
Synth_volume( &this->square_synth, (int)(v * factor / 2 / 15 / FP_ONE_VOLUME) );
}
#endif
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