88 lines
2.1 KiB
C++
88 lines
2.1 KiB
C++
// Turbo Grafx 16 (PC Engine) PSG sound chip emulator
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// Game_Music_Emu $vers
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#ifndef HES_APU_H
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#define HES_APU_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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class Hes_Apu {
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public:
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// Basics
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// Sets buffer(s) to generate sound into, or 0 to mute. If only center is not 0,
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// output is mono.
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void set_output( Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
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// Emulates to time t, then writes data to addr
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void write_data( blip_time_t t, int addr, int data );
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// Emulates to time t, then subtracts t from the current time.
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// OK if previous write call had time slightly after t.
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void end_frame( blip_time_t t );
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// More features
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// Resets sound chip
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void reset();
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// Same as set_output(), but for a particular channel
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enum { osc_count = 6 }; // 0 <= chan < osc_count
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void set_output( int chan, Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
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// Sets treble equalization
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void treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
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// Sets overall volume, where 1.0 is normal
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void volume( double v ) { synth.volume( 1.8 / osc_count / amp_range * v ); }
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// Registers are at io_addr to io_addr+io_size-1
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enum { io_addr = 0x0800 };
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enum { io_size = 10 };
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// Implementation
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public:
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Hes_Apu();
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typedef BOOST::uint8_t byte;
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private:
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enum { amp_range = 0x8000 };
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struct Osc
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{
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byte wave [32];
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int delay;
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int period;
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int phase;
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int noise_delay;
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byte noise;
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unsigned lfsr;
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byte control;
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byte balance;
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byte dac;
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short volume [2];
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int last_amp [2];
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blip_time_t last_time;
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Blip_Buffer* output [2];
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Blip_Buffer* outputs [3];
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};
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Osc oscs [osc_count];
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int latch;
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int balance;
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Blip_Synth_Fast synth;
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void balance_changed( Osc& );
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static void run_osc( Blip_Synth_Fast&, Osc&, blip_time_t );
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};
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inline void Hes_Apu::set_output( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r )
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{
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for ( int i = osc_count; --i >= 0; )
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set_output( i, c, l, r );
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}
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#endif
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