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// NES FDS sound chip emulator
// Game_Music_Emu 0.6-pre
#ifndef NES_FDS_APU_H
#define NES_FDS_APU_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Nes_Fds_Apu {
public:
// setup
void set_tempo( double );
enum { osc_count = 1 };
void set_output( Blip_Buffer* buf );
void volume( double );
void treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
// emulation
void reset();
enum { io_addr = 0x4040 };
enum { io_size = 0x53 };
void write( blip_time_t time, unsigned addr, int data );
int read( blip_time_t time, unsigned addr );
void end_frame( blip_time_t );
public:
Nes_Fds_Apu();
void write_( unsigned addr, int data );
BLARGG_DISABLE_NOTHROW
void set_output( int index, Blip_Buffer* center,
Blip_Buffer* left_ignored = NULL, Blip_Buffer* right_ignored = NULL );
BLARGG_DEPRECATED_TEXT( enum { start_addr = 0x4040 }; )
BLARGG_DEPRECATED_TEXT( enum { end_addr = 0x4092 }; )
BLARGG_DEPRECATED_TEXT( enum { reg_count = end_addr - start_addr + 1 }; )
void osc_output( int, Blip_Buffer* );
private:
enum { wave_size = 0x40 };
enum { master_vol_max = 10 };
enum { vol_max = 0x20 };
enum { wave_sample_max = 0x3F };
unsigned char regs_ [io_size];// last written value to registers
enum { lfo_base_tempo = 8 };
int lfo_tempo; // normally 8; adjusted by set_tempo()
int env_delay;
int env_speed;
int env_gain;
int sweep_delay;
int sweep_speed;
int sweep_gain;
int wave_pos;
int last_amp;
blip_time_t wave_fract;
int mod_fract;
int mod_pos;
int mod_write_pos;
unsigned char mod_wave [wave_size];
// synthesis
blip_time_t last_time;
Blip_Buffer* output_;
Blip_Synth_Fast synth;
// allow access to registers by absolute address (i.e. 0x4080)
unsigned char& regs( unsigned addr ) { return regs_ [addr - io_addr]; }
void run_until( blip_time_t );
};
inline void Nes_Fds_Apu::volume( double v )
{
synth.volume( 0.14 / master_vol_max / vol_max / wave_sample_max * v );
}
inline void Nes_Fds_Apu::set_output( Blip_Buffer* b )
{
output_ = b;
}
inline void Nes_Fds_Apu::set_output( int i, Blip_Buffer* buf, Blip_Buffer*, Blip_Buffer* )
{
assert( (unsigned) i < osc_count );
output_ = buf;
}
inline void Nes_Fds_Apu::end_frame( blip_time_t end_time )
{
if ( end_time > last_time )
run_until( end_time );
last_time -= end_time;
assert( last_time >= 0 );
}
inline void Nes_Fds_Apu::write( blip_time_t time, unsigned addr, int data )
{
run_until( time );
write_( addr, data );
}
inline int Nes_Fds_Apu::read( blip_time_t time, unsigned addr )
{
run_until( time );
int result = 0xFF;
switch ( addr )
{
case 0x4090:
result = env_gain;
break;
case 0x4092:
result = sweep_gain;
break;
default:
unsigned i = addr - io_addr;
if ( i < wave_size )
result = regs_ [i];
}
return result | 0x40;
}
inline Nes_Fds_Apu::Nes_Fds_Apu()
{
lfo_tempo = lfo_base_tempo;
set_output( NULL );
volume( 1.0 );
reset();
}
#endif
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