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