1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/fast_dsp/SPC_DSP.h	Fri Oct 21 05:53:11 2011 -0700
     1.3 @@ -0,0 +1,212 @@
     1.4 +// Fast SNES SPC-700 DSP emulator (about 3x speed of accurate one)
     1.5 +
     1.6 +// snes_spc 0.9.0
     1.7 +#ifndef SPC_DSP_H
     1.8 +#define SPC_DSP_H
     1.9 +
    1.10 +#include "blargg_common.h"
    1.11 +
    1.12 +class SPC_DSP {
    1.13 +public:
    1.14 +	typedef BOOST::uint8_t uint8_t;
    1.15 +	
    1.16 +// Setup
    1.17 +	
    1.18 +	// Initializes DSP and has it use the 64K RAM provided
    1.19 +	void init( void* ram_64k );
    1.20 +
    1.21 +	// Sets destination for output samples. If out is NULL or out_size is 0,
    1.22 +	// doesn't generate any.
    1.23 +	typedef short sample_t;
    1.24 +	void set_output( sample_t* out, int out_size );
    1.25 +
    1.26 +	// Number of samples written to output since it was last set, always
    1.27 +	// a multiple of 2. Undefined if more samples were generated than
    1.28 +	// output buffer could hold.
    1.29 +	int sample_count() const;
    1.30 +
    1.31 +// Emulation
    1.32 +	
    1.33 +	// Resets DSP to power-on state
    1.34 +	void reset();
    1.35 +
    1.36 +	// Emulates pressing reset switch on SNES
    1.37 +	void soft_reset();
    1.38 +	
    1.39 +	// Reads/writes DSP registers. For accuracy, you must first call spc_run_dsp()
    1.40 +	// to catch the DSP up to present.
    1.41 +	int  read ( int addr ) const;
    1.42 +	void write( int addr, int data );
    1.43 +
    1.44 +	// Runs DSP for specified number of clocks (~1024000 per second). Every 32 clocks
    1.45 +	// a pair of samples is be generated.
    1.46 +	void run( int clock_count );
    1.47 +
    1.48 +// Sound control
    1.49 +
    1.50 +	// Mutes voices corresponding to non-zero bits in mask (overrides VxVOL with 0).
    1.51 +	// Reduces emulation accuracy.
    1.52 +	enum { voice_count = 8 };
    1.53 +	void mute_voices( int mask );
    1.54 +
    1.55 +	// If true, prevents channels and global volumes from being phase-negated
    1.56 +	void disable_surround( bool disable = true );
    1.57 +
    1.58 +// State
    1.59 +	
    1.60 +	// Resets DSP and uses supplied values to initialize registers
    1.61 +	enum { register_count = 128 };
    1.62 +	void load( uint8_t const regs [register_count] );
    1.63 +
    1.64 +// DSP register addresses
    1.65 +
    1.66 +	// Global registers
    1.67 +	enum {
    1.68 +	    r_mvoll = 0x0C, r_mvolr = 0x1C,
    1.69 +	    r_evoll = 0x2C, r_evolr = 0x3C,
    1.70 +	    r_kon   = 0x4C, r_koff  = 0x5C,
    1.71 +	    r_flg   = 0x6C, r_endx  = 0x7C,
    1.72 +	    r_efb   = 0x0D, r_pmon  = 0x2D,
    1.73 +	    r_non   = 0x3D, r_eon   = 0x4D,
    1.74 +	    r_dir   = 0x5D, r_esa   = 0x6D,
    1.75 +	    r_edl   = 0x7D,
    1.76 +	    r_fir   = 0x0F // 8 coefficients at 0x0F, 0x1F ... 0x7F
    1.77 +	};
    1.78 +
    1.79 +	// Voice registers
    1.80 +	enum {
    1.81 +		v_voll   = 0x00, v_volr   = 0x01,
    1.82 +		v_pitchl = 0x02, v_pitchh = 0x03,
    1.83 +		v_srcn   = 0x04, v_adsr0  = 0x05,
    1.84 +		v_adsr1  = 0x06, v_gain   = 0x07,
    1.85 +		v_envx   = 0x08, v_outx   = 0x09
    1.86 +	};
    1.87 +
    1.88 +public:
    1.89 +	enum { extra_size = 16 };
    1.90 +	sample_t* extra()               { return m.extra; }
    1.91 +	sample_t const* out_pos() const { return m.out; }
    1.92 +public:
    1.93 +	BLARGG_DISABLE_NOTHROW
    1.94 +	
    1.95 +	typedef BOOST::int8_t   int8_t;
    1.96 +	typedef BOOST::int16_t int16_t;
    1.97 +	
    1.98 +	enum { echo_hist_size = 8 };
    1.99 +	
   1.100 +	enum env_mode_t { env_release, env_attack, env_decay, env_sustain };
   1.101 +	enum { brr_buf_size = 12 };
   1.102 +	struct voice_t
   1.103 +	{
   1.104 +		int buf [brr_buf_size*2];// decoded samples (twice the size to simplify wrap handling)
   1.105 +		int* buf_pos;           // place in buffer where next samples will be decoded
   1.106 +		int interp_pos;         // relative fractional position in sample (0x1000 = 1.0)
   1.107 +		int brr_addr;           // address of current BRR block
   1.108 +		int brr_offset;         // current decoding offset in BRR block
   1.109 +		int kon_delay;          // KON delay/current setup phase
   1.110 +		env_mode_t env_mode;
   1.111 +		int env;                // current envelope level
   1.112 +		int hidden_env;         // used by GAIN mode 7, very obscure quirk
   1.113 +		int volume [2];         // copy of volume from DSP registers, with surround disabled
   1.114 +		int enabled;            // -1 if enabled, 0 if muted
   1.115 +	};
   1.116 +private:
   1.117 +	struct state_t
   1.118 +	{
   1.119 +		uint8_t regs [register_count];
   1.120 +		
   1.121 +		// Echo history keeps most recent 8 samples (twice the size to simplify wrap handling)
   1.122 +		int echo_hist [echo_hist_size * 2] [2];
   1.123 +		int (*echo_hist_pos) [2]; // &echo_hist [0 to 7]
   1.124 +		
   1.125 +		int every_other_sample; // toggles every sample
   1.126 +		int kon;                // KON value when last checked
   1.127 +		int noise;
   1.128 +		int echo_offset;        // offset from ESA in echo buffer
   1.129 +		int echo_length;        // number of bytes that echo_offset will stop at
   1.130 +		int phase;              // next clock cycle to run (0-31)
   1.131 +		unsigned counters [4];
   1.132 +		
   1.133 +		int new_kon;
   1.134 +		int t_koff;
   1.135 +		
   1.136 +		voice_t voices [voice_count];
   1.137 +		
   1.138 +		unsigned* counter_select [32];
   1.139 +		
   1.140 +		// non-emulation state
   1.141 +		uint8_t* ram; // 64K shared RAM between DSP and SMP
   1.142 +		int mute_mask;
   1.143 +		int surround_threshold;
   1.144 +		sample_t* out;
   1.145 +		sample_t* out_end;
   1.146 +		sample_t* out_begin;
   1.147 +		sample_t extra [extra_size];
   1.148 +	};
   1.149 +	state_t m;
   1.150 +	
   1.151 +	void init_counter();
   1.152 +	void run_counter( int );
   1.153 +	void soft_reset_common();
   1.154 +	void write_outline( int addr, int data );
   1.155 +	void update_voice_vol( int addr );
   1.156 +};
   1.157 +
   1.158 +#include <assert.h>
   1.159 +
   1.160 +inline int SPC_DSP::sample_count() const { return m.out - m.out_begin; }
   1.161 +
   1.162 +inline int SPC_DSP::read( int addr ) const
   1.163 +{
   1.164 +	assert( (unsigned) addr < register_count );
   1.165 +	return m.regs [addr];
   1.166 +}
   1.167 +
   1.168 +inline void SPC_DSP::update_voice_vol( int addr )
   1.169 +{
   1.170 +	int l = (int8_t) m.regs [addr + v_voll];
   1.171 +	int r = (int8_t) m.regs [addr + v_volr];
   1.172 +	
   1.173 +	if ( l * r < m.surround_threshold )
   1.174 +	{
   1.175 +		// signs differ, so negate those that are negative
   1.176 +		l ^= l >> 7;
   1.177 +		r ^= r >> 7;
   1.178 +	}
   1.179 +	
   1.180 +	voice_t& v = m.voices [addr >> 4];
   1.181 +	int enabled = v.enabled;
   1.182 +	v.volume [0] = l & enabled;
   1.183 +	v.volume [1] = r & enabled;
   1.184 +}
   1.185 +
   1.186 +inline void SPC_DSP::write( int addr, int data )
   1.187 +{
   1.188 +	assert( (unsigned) addr < register_count );
   1.189 +	
   1.190 +	m.regs [addr] = (uint8_t) data;
   1.191 +	int low = addr & 0x0F;
   1.192 +	if ( low < 0x2 ) // voice volumes
   1.193 +	{
   1.194 +		update_voice_vol( low ^ addr );
   1.195 +	}
   1.196 +	else if ( low == 0xC )
   1.197 +	{
   1.198 +		if ( addr == r_kon )
   1.199 +			m.new_kon = (uint8_t) data;
   1.200 +		
   1.201 +		if ( addr == r_endx ) // always cleared, regardless of data written
   1.202 +			m.regs [r_endx] = 0;
   1.203 +	}
   1.204 +}
   1.205 +
   1.206 +inline void SPC_DSP::disable_surround( bool disable )
   1.207 +{
   1.208 +	m.surround_threshold = disable ? 0 : -0x4000;
   1.209 +}
   1.210 +
   1.211 +#define SPC_NO_COPY_STATE_FUNCS 1
   1.212 +
   1.213 +#define SPC_LESS_ACCURATE 1
   1.214 +
   1.215 +#endif