rlm@0: // Fast SNES SPC-700 DSP emulator (about 3x speed of accurate one)
rlm@0: 
rlm@0: // snes_spc 0.9.0
rlm@0: #ifndef SPC_DSP_H
rlm@0: #define SPC_DSP_H
rlm@0: 
rlm@0: #include "blargg_common.h"
rlm@0: 
rlm@0: class SPC_DSP {
rlm@0: public:
rlm@0: 	typedef BOOST::uint8_t uint8_t;
rlm@0: 	
rlm@0: // Setup
rlm@0: 	
rlm@0: 	// Initializes DSP and has it use the 64K RAM provided
rlm@0: 	void init( void* ram_64k );
rlm@0: 
rlm@0: 	// Sets destination for output samples. If out is NULL or out_size is 0,
rlm@0: 	// doesn't generate any.
rlm@0: 	typedef short sample_t;
rlm@0: 	void set_output( sample_t* out, int out_size );
rlm@0: 
rlm@0: 	// Number of samples written to output since it was last set, always
rlm@0: 	// a multiple of 2. Undefined if more samples were generated than
rlm@0: 	// output buffer could hold.
rlm@0: 	int sample_count() const;
rlm@0: 
rlm@0: // Emulation
rlm@0: 	
rlm@0: 	// Resets DSP to power-on state
rlm@0: 	void reset();
rlm@0: 
rlm@0: 	// Emulates pressing reset switch on SNES
rlm@0: 	void soft_reset();
rlm@0: 	
rlm@0: 	// Reads/writes DSP registers. For accuracy, you must first call spc_run_dsp()
rlm@0: 	// to catch the DSP up to present.
rlm@0: 	int  read ( int addr ) const;
rlm@0: 	void write( int addr, int data );
rlm@0: 
rlm@0: 	// Runs DSP for specified number of clocks (~1024000 per second). Every 32 clocks
rlm@0: 	// a pair of samples is be generated.
rlm@0: 	void run( int clock_count );
rlm@0: 
rlm@0: // Sound control
rlm@0: 
rlm@0: 	// Mutes voices corresponding to non-zero bits in mask (overrides VxVOL with 0).
rlm@0: 	// Reduces emulation accuracy.
rlm@0: 	enum { voice_count = 8 };
rlm@0: 	void mute_voices( int mask );
rlm@0: 
rlm@0: 	// If true, prevents channels and global volumes from being phase-negated
rlm@0: 	void disable_surround( bool disable = true );
rlm@0: 
rlm@0: // State
rlm@0: 	
rlm@0: 	// Resets DSP and uses supplied values to initialize registers
rlm@0: 	enum { register_count = 128 };
rlm@0: 	void load( uint8_t const regs [register_count] );
rlm@0: 
rlm@0: // DSP register addresses
rlm@0: 
rlm@0: 	// Global registers
rlm@0: 	enum {
rlm@0: 	    r_mvoll = 0x0C, r_mvolr = 0x1C,
rlm@0: 	    r_evoll = 0x2C, r_evolr = 0x3C,
rlm@0: 	    r_kon   = 0x4C, r_koff  = 0x5C,
rlm@0: 	    r_flg   = 0x6C, r_endx  = 0x7C,
rlm@0: 	    r_efb   = 0x0D, r_pmon  = 0x2D,
rlm@0: 	    r_non   = 0x3D, r_eon   = 0x4D,
rlm@0: 	    r_dir   = 0x5D, r_esa   = 0x6D,
rlm@0: 	    r_edl   = 0x7D,
rlm@0: 	    r_fir   = 0x0F // 8 coefficients at 0x0F, 0x1F ... 0x7F
rlm@0: 	};
rlm@0: 
rlm@0: 	// Voice registers
rlm@0: 	enum {
rlm@0: 		v_voll   = 0x00, v_volr   = 0x01,
rlm@0: 		v_pitchl = 0x02, v_pitchh = 0x03,
rlm@0: 		v_srcn   = 0x04, v_adsr0  = 0x05,
rlm@0: 		v_adsr1  = 0x06, v_gain   = 0x07,
rlm@0: 		v_envx   = 0x08, v_outx   = 0x09
rlm@0: 	};
rlm@0: 
rlm@0: public:
rlm@0: 	enum { extra_size = 16 };
rlm@0: 	sample_t* extra()               { return m.extra; }
rlm@0: 	sample_t const* out_pos() const { return m.out; }
rlm@0: public:
rlm@0: 	BLARGG_DISABLE_NOTHROW
rlm@0: 	
rlm@0: 	typedef BOOST::int8_t   int8_t;
rlm@0: 	typedef BOOST::int16_t int16_t;
rlm@0: 	
rlm@0: 	enum { echo_hist_size = 8 };
rlm@0: 	
rlm@0: 	enum env_mode_t { env_release, env_attack, env_decay, env_sustain };
rlm@0: 	enum { brr_buf_size = 12 };
rlm@0: 	struct voice_t
rlm@0: 	{
rlm@0: 		int buf [brr_buf_size*2];// decoded samples (twice the size to simplify wrap handling)
rlm@0: 		int* buf_pos;           // place in buffer where next samples will be decoded
rlm@0: 		int interp_pos;         // relative fractional position in sample (0x1000 = 1.0)
rlm@0: 		int brr_addr;           // address of current BRR block
rlm@0: 		int brr_offset;         // current decoding offset in BRR block
rlm@0: 		int kon_delay;          // KON delay/current setup phase
rlm@0: 		env_mode_t env_mode;
rlm@0: 		int env;                // current envelope level
rlm@0: 		int hidden_env;         // used by GAIN mode 7, very obscure quirk
rlm@0: 		int volume [2];         // copy of volume from DSP registers, with surround disabled
rlm@0: 		int enabled;            // -1 if enabled, 0 if muted
rlm@0: 	};
rlm@0: private:
rlm@0: 	struct state_t
rlm@0: 	{
rlm@0: 		uint8_t regs [register_count];
rlm@0: 		
rlm@0: 		// Echo history keeps most recent 8 samples (twice the size to simplify wrap handling)
rlm@0: 		int echo_hist [echo_hist_size * 2] [2];
rlm@0: 		int (*echo_hist_pos) [2]; // &echo_hist [0 to 7]
rlm@0: 		
rlm@0: 		int every_other_sample; // toggles every sample
rlm@0: 		int kon;                // KON value when last checked
rlm@0: 		int noise;
rlm@0: 		int echo_offset;        // offset from ESA in echo buffer
rlm@0: 		int echo_length;        // number of bytes that echo_offset will stop at
rlm@0: 		int phase;              // next clock cycle to run (0-31)
rlm@0: 		unsigned counters [4];
rlm@0: 		
rlm@0: 		int new_kon;
rlm@0: 		int t_koff;
rlm@0: 		
rlm@0: 		voice_t voices [voice_count];
rlm@0: 		
rlm@0: 		unsigned* counter_select [32];
rlm@0: 		
rlm@0: 		// non-emulation state
rlm@0: 		uint8_t* ram; // 64K shared RAM between DSP and SMP
rlm@0: 		int mute_mask;
rlm@0: 		int surround_threshold;
rlm@0: 		sample_t* out;
rlm@0: 		sample_t* out_end;
rlm@0: 		sample_t* out_begin;
rlm@0: 		sample_t extra [extra_size];
rlm@0: 	};
rlm@0: 	state_t m;
rlm@0: 	
rlm@0: 	void init_counter();
rlm@0: 	void run_counter( int );
rlm@0: 	void soft_reset_common();
rlm@0: 	void write_outline( int addr, int data );
rlm@0: 	void update_voice_vol( int addr );
rlm@0: };
rlm@0: 
rlm@0: #include <assert.h>
rlm@0: 
rlm@0: inline int SPC_DSP::sample_count() const { return m.out - m.out_begin; }
rlm@0: 
rlm@0: inline int SPC_DSP::read( int addr ) const
rlm@0: {
rlm@0: 	assert( (unsigned) addr < register_count );
rlm@0: 	return m.regs [addr];
rlm@0: }
rlm@0: 
rlm@0: inline void SPC_DSP::update_voice_vol( int addr )
rlm@0: {
rlm@0: 	int l = (int8_t) m.regs [addr + v_voll];
rlm@0: 	int r = (int8_t) m.regs [addr + v_volr];
rlm@0: 	
rlm@0: 	if ( l * r < m.surround_threshold )
rlm@0: 	{
rlm@0: 		// signs differ, so negate those that are negative
rlm@0: 		l ^= l >> 7;
rlm@0: 		r ^= r >> 7;
rlm@0: 	}
rlm@0: 	
rlm@0: 	voice_t& v = m.voices [addr >> 4];
rlm@0: 	int enabled = v.enabled;
rlm@0: 	v.volume [0] = l & enabled;
rlm@0: 	v.volume [1] = r & enabled;
rlm@0: }
rlm@0: 
rlm@0: inline void SPC_DSP::write( int addr, int data )
rlm@0: {
rlm@0: 	assert( (unsigned) addr < register_count );
rlm@0: 	
rlm@0: 	m.regs [addr] = (uint8_t) data;
rlm@0: 	int low = addr & 0x0F;
rlm@0: 	if ( low < 0x2 ) // voice volumes
rlm@0: 	{
rlm@0: 		update_voice_vol( low ^ addr );
rlm@0: 	}
rlm@0: 	else if ( low == 0xC )
rlm@0: 	{
rlm@0: 		if ( addr == r_kon )
rlm@0: 			m.new_kon = (uint8_t) data;
rlm@0: 		
rlm@0: 		if ( addr == r_endx ) // always cleared, regardless of data written
rlm@0: 			m.regs [r_endx] = 0;
rlm@0: 	}
rlm@0: }
rlm@0: 
rlm@0: inline void SPC_DSP::disable_surround( bool disable )
rlm@0: {
rlm@0: 	m.surround_threshold = disable ? 0 : -0x4000;
rlm@0: }
rlm@0: 
rlm@0: #define SPC_NO_COPY_STATE_FUNCS 1
rlm@0: 
rlm@0: #define SPC_LESS_ACCURATE 1
rlm@0: 
rlm@0: #endif