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// Turbo Grafx 16 (PC Engine) ADPCM sound chip emulator
// Game_Music_Emu 0.6-pre
#ifndef HES_APU_ADPCM_H
#define HES_APU_ADPCM_H
#include "blargg_common.h"
#include "Blip_Buffer.h"
class Hes_Apu_Adpcm {
public:
// Basics
// Sets buffer(s) to generate sound into, or 0 to mute. If only center is not 0,
// output is mono.
void set_output( Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
// Emulates to time t, then writes data to addr
void write_data( blip_time_t t, int addr, int data );
// Emulates to time t, then reads from addr
int read_data( blip_time_t t, int addr );
// Emulates to time t, then subtracts t from the current time.
// OK if previous write call had time slightly after t.
void end_frame( blip_time_t t );
// More features
// Resets sound chip
void reset();
// Same as set_output(), but for a particular channel
enum { osc_count = 1 }; // 0 <= chan < osc_count
void set_output( int chan, Blip_Buffer* center, Blip_Buffer* left = NULL, Blip_Buffer* right = NULL );
// Sets treble equalization
void treble_eq( blip_eq_t const& eq ) { synth.treble_eq( eq ); }
// Sets overall volume, where 1.0 is normal
void volume( double v ) { synth.volume( 0.6 / osc_count / amp_range * v ); }
// Registers are at io_addr to io_addr+io_size-1
enum { io_addr = 0x1800 };
enum { io_size = 0x400 };
// Implementation
public:
Hes_Apu_Adpcm();
typedef BOOST::uint8_t byte;
private:
enum { amp_range = 2048 };
struct State
{
byte pcmbuf [0x10000];
byte port [0x10];
int ad_sample;
int ad_ref_index;
bool ad_low_nibble;
int freq;
unsigned short addr;
unsigned short writeptr;
unsigned short readptr;
unsigned short playptr;
byte playflag;
byte repeatflag;
int length;
int playlength;
int playedsamplecount;
int volume;
int fadetimer;
int fadecount;
};
State state;
Blip_Synth_Fast synth;
Blip_Buffer* output;
blip_time_t last_time;
double next_timer;
int last_amp;
void run_until( blip_time_t );
int adpcm_decode( int );
};
inline void Hes_Apu_Adpcm::set_output( Blip_Buffer* c, Blip_Buffer* l, Blip_Buffer* r )
{
set_output( 0, c, l, r );
}
#endif
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