diff options
Diffstat (limited to 'gme/Sap_Apu.h')
-rw-r--r-- | gme/Sap_Apu.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/gme/Sap_Apu.h b/gme/Sap_Apu.h new file mode 100644 index 00000000..c71ce31e --- /dev/null +++ b/gme/Sap_Apu.h @@ -0,0 +1,77 @@ +// Atari POKEY sound chip emulator + +// Game_Music_Emu 0.5.2 +#ifndef SAP_APU_H +#define SAP_APU_H + +#include "blargg_common.h" +#include "Blip_Buffer.h" + +class Sap_Apu_Impl; + +class Sap_Apu { +public: + enum { osc_count = 4 }; + void osc_output( int index, Blip_Buffer* ); + + void reset( Sap_Apu_Impl* ); + + enum { start_addr = 0xD200 }; + enum { end_addr = 0xD209 }; + void write_data( blip_time_t, unsigned addr, int data ); + + void end_frame( blip_time_t ); + +public: + Sap_Apu(); +private: + struct osc_t + { + unsigned char regs [2]; + unsigned char phase; + unsigned char invert; + int last_amp; + blip_time_t delay; + blip_time_t period; // always recalculated before use; here for convenience + Blip_Buffer* output; + }; + osc_t oscs [osc_count]; + Sap_Apu_Impl* impl; + blip_time_t last_time; + int poly5_pos; + int poly4_pos; + int polym_pos; + int control; + + void calc_periods(); + void run_until( blip_time_t ); + + enum { poly4_len = (1L << 4) - 1 }; + enum { poly9_len = (1L << 9) - 1 }; + enum { poly17_len = (1L << 17) - 1 }; + friend class Sap_Apu_Impl; +}; + +// Common tables and Blip_Synth that can be shared among multiple Sap_Apu objects +class Sap_Apu_Impl { +public: + Blip_Synth<blip_good_quality,1> synth; + + Sap_Apu_Impl(); + void volume( double d ) { synth.volume( 1.0 / Sap_Apu::osc_count / 30 * d ); } + +private: + typedef unsigned char byte; + byte poly4 [Sap_Apu::poly4_len / 8 + 1]; + byte poly9 [Sap_Apu::poly9_len / 8 + 1]; + byte poly17 [Sap_Apu::poly17_len / 8 + 1]; + friend class Sap_Apu; +}; + +inline void Sap_Apu::osc_output( int i, Blip_Buffer* b ) +{ + assert( (unsigned) i < osc_count ); + oscs [i].output = b; +} + +#endif |