107 lines
2.3 KiB
C++
107 lines
2.3 KiB
C++
// Konami SCC sound chip emulator
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// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
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#ifndef KSS_SCC_APU_H
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#define KSS_SCC_APU_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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#include <string.h>
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class Scc_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 = 0x90 };
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void write( blip_time_t time, int reg, 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 to 4. If buffer is NULL, the specified oscillator is muted.
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enum { osc_count = 5 };
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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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Scc_Apu();
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private:
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enum { amp_range = 0x8000 };
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struct osc_t
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{
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int delay;
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int phase;
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int last_amp;
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Blip_Buffer* output;
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};
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osc_t oscs [osc_count];
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blip_time_t last_time;
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unsigned char regs [reg_count];
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Blip_Synth<blip_med_quality,1> synth;
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void run_until( blip_time_t );
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};
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inline void Scc_Apu::volume( double v ) { synth.volume( 0.43 / osc_count / amp_range * v ); }
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inline void Scc_Apu::treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
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inline void Scc_Apu::osc_output( int index, Blip_Buffer* b )
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{
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assert( (unsigned) index < osc_count );
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oscs [index].output = b;
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}
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inline void Scc_Apu::write( blip_time_t time, int addr, int data )
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{
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assert( (unsigned) addr < reg_count );
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run_until( time );
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regs [addr] = data;
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}
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inline void Scc_Apu::end_frame( blip_time_t end_time )
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{
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if ( end_time > last_time )
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run_until( end_time );
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last_time -= end_time;
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assert( last_time >= 0 );
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}
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inline void Scc_Apu::output( Blip_Buffer* buf )
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{
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for ( int i = 0; i < osc_count; i++ )
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oscs [i].output = buf;
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}
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inline Scc_Apu::Scc_Apu()
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{
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output( 0 );
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}
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inline void Scc_Apu::reset()
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{
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last_time = 0;
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for ( int i = 0; i < osc_count; i++ )
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memset( &oscs [i], 0, offsetof (osc_t,output) );
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memset( regs, 0, sizeof regs );
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}
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#endif
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