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Diffstat (limited to 'gme/Nes_Fme7_Apu.h')
-rw-r--r-- | gme/Nes_Fme7_Apu.h | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/gme/Nes_Fme7_Apu.h b/gme/Nes_Fme7_Apu.h new file mode 100644 index 00000000..eb60af03 --- /dev/null +++ b/gme/Nes_Fme7_Apu.h @@ -0,0 +1,131 @@ +// Sunsoft FME-7 sound emulator + +// Game_Music_Emu 0.5.2 +#ifndef NES_FME7_APU_H +#define NES_FME7_APU_H + +#include "blargg_common.h" +#include "Blip_Buffer.h" + +struct fme7_apu_state_t +{ + enum { reg_count = 14 }; + BOOST::uint8_t regs [reg_count]; + BOOST::uint8_t phases [3]; // 0 or 1 + BOOST::uint8_t latch; + BOOST::uint16_t delays [3]; // a, b, c +}; + +class Nes_Fme7_Apu : private fme7_apu_state_t { +public: + // See Nes_Apu.h for reference + void reset(); + void volume( double ); + void treble_eq( blip_eq_t const& ); + void output( Blip_Buffer* ); + enum { osc_count = 3 }; + void osc_output( int index, Blip_Buffer* ); + void end_frame( blip_time_t ); + void save_state( fme7_apu_state_t* ) const; + void load_state( fme7_apu_state_t const& ); + + // Mask and addresses of registers + enum { addr_mask = 0xE000 }; + enum { data_addr = 0xE000 }; + enum { latch_addr = 0xC000 }; + + // (addr & addr_mask) == latch_addr + void write_latch( int ); + + // (addr & addr_mask) == data_addr + void write_data( blip_time_t, int data ); + +public: + Nes_Fme7_Apu(); + BLARGG_DISABLE_NOTHROW +private: + // noncopyable + Nes_Fme7_Apu( const Nes_Fme7_Apu& ); + Nes_Fme7_Apu& operator = ( const Nes_Fme7_Apu& ); + + static unsigned char const amp_table [16]; + + struct { + Blip_Buffer* output; + int last_amp; + } oscs [osc_count]; + blip_time_t last_time; + + enum { amp_range = 192 }; // can be any value; this gives best error/quality tradeoff + Blip_Synth<blip_good_quality,1> synth; + + void run_until( blip_time_t ); +}; + +inline void Nes_Fme7_Apu::volume( double v ) +{ + synth.volume( 0.38 / amp_range * v ); // to do: fine-tune +} + +inline void Nes_Fme7_Apu::treble_eq( blip_eq_t const& eq ) +{ + synth.treble_eq( eq ); +} + +inline void Nes_Fme7_Apu::osc_output( int i, Blip_Buffer* buf ) +{ + assert( (unsigned) i < osc_count ); + oscs [i].output = buf; +} + +inline void Nes_Fme7_Apu::output( Blip_Buffer* buf ) +{ + for ( int i = 0; i < osc_count; i++ ) + osc_output( i, buf ); +} + +inline Nes_Fme7_Apu::Nes_Fme7_Apu() +{ + output( NULL ); + volume( 1.0 ); + reset(); +} + +inline void Nes_Fme7_Apu::write_latch( int data ) { latch = data; } + +inline void Nes_Fme7_Apu::write_data( blip_time_t time, int data ) +{ + if ( (unsigned) latch >= reg_count ) + { + #ifdef dprintf + dprintf( "FME7 write to %02X (past end of sound registers)\n", (int) latch ); + #endif + return; + } + + run_until( time ); + regs [latch] = data; +} + +inline void Nes_Fme7_Apu::end_frame( blip_time_t time ) +{ + if ( time > last_time ) + run_until( time ); + + assert( last_time >= time ); + last_time -= time; +} + +inline void Nes_Fme7_Apu::save_state( fme7_apu_state_t* out ) const +{ + *out = *this; +} + +inline void Nes_Fme7_Apu::load_state( fme7_apu_state_t const& in ) +{ + reset(); + fme7_apu_state_t* state = this; + *state = in; +} + +#endif |