78 lines
1.6 KiB
C++
78 lines
1.6 KiB
C++
// Atari POKEY sound chip emulator
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// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
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#ifndef SAP_APU_H
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#define SAP_APU_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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class Sap_Apu_Impl;
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class Sap_Apu {
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public:
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enum { osc_count = 4 };
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void osc_output( int index, Blip_Buffer* );
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void reset( Sap_Apu_Impl* );
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enum { start_addr = 0xD200 };
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enum { end_addr = 0xD209 };
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void write_data( blip_time_t, unsigned addr, int data );
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void end_frame( blip_time_t );
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public:
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Sap_Apu();
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private:
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struct osc_t
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{
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unsigned char regs [2];
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unsigned char phase;
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unsigned char invert;
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int last_amp;
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blip_time_t delay;
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blip_time_t period; // always recalculated before use; here for convenience
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Blip_Buffer* output;
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};
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osc_t oscs [osc_count];
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Sap_Apu_Impl* impl;
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blip_time_t last_time;
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int poly5_pos;
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int poly4_pos;
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int polym_pos;
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int control;
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void calc_periods();
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void run_until( blip_time_t );
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enum { poly4_len = (1L << 4) - 1 };
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enum { poly9_len = (1L << 9) - 1 };
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enum { poly17_len = (1L << 17) - 1 };
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friend class Sap_Apu_Impl;
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};
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// Common tables and Blip_Synth that can be shared among multiple Sap_Apu objects
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class Sap_Apu_Impl {
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public:
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Blip_Synth<blip_good_quality,1> synth;
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Sap_Apu_Impl();
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void volume( double d ) { synth.volume( 1.0 / Sap_Apu::osc_count / 30 * d ); }
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private:
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typedef unsigned char byte;
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byte poly4 [Sap_Apu::poly4_len / 8 + 1];
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byte poly9 [Sap_Apu::poly9_len / 8 + 1];
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byte poly17 [Sap_Apu::poly17_len / 8 + 1];
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friend class Sap_Apu;
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};
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inline void Sap_Apu::osc_output( int i, Blip_Buffer* b )
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{
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assert( (unsigned) i < osc_count );
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oscs [i].output = b;
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}
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#endif
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