95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
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// Turbo Grafx 16 (PC Engine) ADPCM sound chip emulator
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// Game_Music_Emu $vers
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#ifndef HES_APU_ADPCM_H
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#define HES_APU_ADPCM_H
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#include "blargg_common.h"
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#include "Blip_Buffer.h"
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class Hes_Apu_Adpcm {
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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 reads from addr
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int read_data( blip_time_t t, int addr );
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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 = 1 }; // 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( 0.6 / 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 = 0x1800 };
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enum { io_size = 0x400 };
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// Implementation
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public:
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Hes_Apu_Adpcm();
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typedef BOOST::uint8_t byte;
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private:
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enum { amp_range = 2048 };
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struct State
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{
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byte pcmbuf [0x10000];
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byte port [0x10];
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int ad_sample;
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int ad_ref_index;
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bool ad_low_nibble;
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int freq;
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unsigned short addr;
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unsigned short writeptr;
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unsigned short readptr;
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unsigned short playptr;
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byte playflag;
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byte repeatflag;
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int length;
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int playlength;
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int playedsamplecount;
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int volume;
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int fadetimer;
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int fadecount;
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};
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State state;
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Blip_Synth_Fast synth;
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Blip_Buffer* output;
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blip_time_t last_time;
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double next_timer;
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int last_amp;
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void run_until( blip_time_t );
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int adpcm_decode( int );
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};
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inline void Hes_Apu_Adpcm::set_output( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r )
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{
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set_output( 0, c, l, r );
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}
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#endif
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