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// Super Nintendo (SNES) SPC DSP emulator
// Game_Music_Emu 0.5.5
#ifndef SPC_DSP_H
#define SPC_DSP_H
#include "blargg_common.h"
class Spc_Dsp {
typedef BOOST::int8_t int8_t;
typedef BOOST::uint8_t uint8_t;
public:
// Keeps pointer to 64K ram
Spc_Dsp( uint8_t* ram );
// Mute voice n if bit n (1 << n) of mask is clear.
enum { voice_count = 8 };
void mute_voices( int mask );
// Clear state and silence everything.
void reset();
// Set gain, where 1.0 is normal. When greater than 1.0, output is clamped to
// the 16-bit sample range.
void set_gain( double );
// If true, prevent channels and global volumes from being phase-negated
void disable_surround( bool disable );
// Read/write register 'n', where n ranges from 0 to register_count - 1.
enum { register_count = 128 };
int read ( int n );
void write( int n, int );
// Run DSP for 'count' samples. Write resulting samples to 'buf' if not NULL.
void run( long count, short* buf = NULL );
// End of public interface
private:
struct raw_voice_t {
int8_t left_vol;
int8_t right_vol;
uint8_t rate [2];
uint8_t waveform;
uint8_t adsr [2]; // envelope rates for attack, decay, and sustain
uint8_t gain; // envelope gain (if not using ADSR)
int8_t envx; // current envelope level
int8_t outx; // current sample
int8_t unused [6];
};
struct globals_t {
int8_t unused1 [12];
int8_t left_volume; // 0C Main Volume Left (-.7)
int8_t echo_feedback; // 0D Echo Feedback (-.7)
int8_t unused2 [14];
int8_t right_volume; // 1C Main Volume Right (-.7)
int8_t unused3 [15];
int8_t left_echo_volume; // 2C Echo Volume Left (-.7)
uint8_t pitch_mods; // 2D Pitch Modulation on/off for each voice
int8_t unused4 [14];
int8_t right_echo_volume; // 3C Echo Volume Right (-.7)
uint8_t noise_enables; // 3D Noise output on/off for each voice
int8_t unused5 [14];
uint8_t key_ons; // 4C Key On for each voice
uint8_t echo_ons; // 4D Echo on/off for each voice
int8_t unused6 [14];
uint8_t key_offs; // 5C key off for each voice (instantiates release mode)
uint8_t wave_page; // 5D source directory (wave table offsets)
int8_t unused7 [14];
uint8_t flags; // 6C flags and noise freq
uint8_t echo_page; // 6D
int8_t unused8 [14];
uint8_t wave_ended; // 7C
uint8_t echo_delay; // 7D ms >> 4
char unused9 [2];
};
union {
raw_voice_t voice [voice_count];
uint8_t reg [register_count];
globals_t g;
};
uint8_t* const ram;
// Cache of echo FIR values for faster access
short fir_coeff [voice_count];
// fir_buf [i + 8] == fir_buf [i], to avoid wrap checking in FIR code
short fir_buf [16] [2];
int fir_offset; // (0 to 7)
enum { emu_gain_bits = 8 };
int emu_gain;
int keyed_on; // 8-bits for 8 voices
int keys;
int echo_ptr;
int noise_amp;
int noise;
int noise_count;
int surround_threshold;
static BOOST::int16_t const gauss [];
enum state_t {
state_attack,
state_decay,
state_sustain,
state_release
};
struct voice_t {
short volume [2];
short fraction;// 12-bit fractional position
short interp3; // most recent four decoded samples
short interp2;
short interp1;
short interp0;
short block_remain; // number of nybbles remaining in current block
unsigned short addr;
short block_header; // header byte from current block
short envcnt;
short envx;
short on_cnt;
short enabled; // 7 if enabled, 31 if disabled
short envstate;
short unused; // pad to power of 2
};
voice_t voice_state [voice_count];
int clock_envelope( int );
};
inline void Spc_Dsp::disable_surround( bool disable ) { surround_threshold = disable ? 0 : -0x7FFF; }
inline void Spc_Dsp::set_gain( double v ) { emu_gain = (int) (v * (1 << emu_gain_bits)); }
inline int Spc_Dsp::read( int i )
{
assert( (unsigned) i < register_count );
return reg [i];
}
#endif
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