153 lines
3.9 KiB
C++
Executable File
153 lines
3.9 KiB
C++
Executable File
// Super Nintendo (SNES) SPC DSP emulator
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// Game_Music_Emu 0.5.2
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#ifndef SPC_DSP_H
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#define SPC_DSP_H
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#include "blargg_common.h"
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class Spc_Dsp {
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typedef BOOST::int8_t int8_t;
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typedef BOOST::uint8_t uint8_t;
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public:
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// Keeps pointer to 64K ram
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Spc_Dsp( uint8_t* ram );
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// Mute voice n if bit n (1 << n) of mask is clear.
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enum { voice_count = 8 };
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void mute_voices( int mask );
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// Clear state and silence everything.
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void reset();
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// Set gain, where 1.0 is normal. When greater than 1.0, output is clamped to
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// the 16-bit sample range.
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void set_gain( double );
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// If true, prevent channels and global volumes from being phase-negated
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void disable_surround( bool disable );
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// Read/write register 'n', where n ranges from 0 to register_count - 1.
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enum { register_count = 128 };
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int read ( int n );
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void write( int n, int );
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// Run DSP for 'count' samples. Write resulting samples to 'buf' if not NULL.
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void run( long count, short* buf = NULL );
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// End of public interface
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private:
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struct raw_voice_t {
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int8_t left_vol;
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int8_t right_vol;
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uint8_t rate [2];
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uint8_t waveform;
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uint8_t adsr [2]; // envelope rates for attack, decay, and sustain
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uint8_t gain; // envelope gain (if not using ADSR)
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int8_t envx; // current envelope level
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int8_t outx; // current sample
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int8_t unused [6];
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};
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struct globals_t {
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int8_t unused1 [12];
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int8_t left_volume; // 0C Main Volume Left (-.7)
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int8_t echo_feedback; // 0D Echo Feedback (-.7)
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int8_t unused2 [14];
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int8_t right_volume; // 1C Main Volume Right (-.7)
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int8_t unused3 [15];
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int8_t left_echo_volume; // 2C Echo Volume Left (-.7)
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uint8_t pitch_mods; // 2D Pitch Modulation on/off for each voice
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int8_t unused4 [14];
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int8_t right_echo_volume; // 3C Echo Volume Right (-.7)
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uint8_t noise_enables; // 3D Noise output on/off for each voice
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int8_t unused5 [14];
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uint8_t key_ons; // 4C Key On for each voice
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uint8_t echo_ons; // 4D Echo on/off for each voice
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int8_t unused6 [14];
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uint8_t key_offs; // 5C key off for each voice (instantiates release mode)
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uint8_t wave_page; // 5D source directory (wave table offsets)
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int8_t unused7 [14];
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uint8_t flags; // 6C flags and noise freq
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uint8_t echo_page; // 6D
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int8_t unused8 [14];
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uint8_t wave_ended; // 7C
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uint8_t echo_delay; // 7D ms >> 4
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char unused9 [2];
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};
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union {
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raw_voice_t voice [voice_count];
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uint8_t reg [register_count];
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globals_t g;
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};
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uint8_t* const ram;
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// Cache of echo FIR values for faster access
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short fir_coeff [voice_count];
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// fir_buf [i + 8] == fir_buf [i], to avoid wrap checking in FIR code
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short fir_buf [16] [2];
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int fir_offset; // (0 to 7)
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enum { emu_gain_bits = 8 };
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int emu_gain;
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int keyed_on; // 8-bits for 8 voices
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int keys;
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int echo_ptr;
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int noise_amp;
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int noise;
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int noise_count;
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int surround_threshold;
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static BOOST::int16_t const gauss [];
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enum state_t {
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state_attack,
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state_decay,
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state_sustain,
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state_release
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};
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struct voice_t {
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short volume [2];
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short fraction;// 12-bit fractional position
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short interp3; // most recent four decoded samples
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short interp2;
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short interp1;
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short interp0;
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short block_remain; // number of nybbles remaining in current block
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unsigned short addr;
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short block_header; // header byte from current block
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short envcnt;
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short envx;
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short on_cnt;
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short enabled; // 7 if enabled, 31 if disabled
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short envstate;
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short unused; // pad to power of 2
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};
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voice_t voice_state [voice_count];
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int clock_envelope( int );
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};
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inline void Spc_Dsp::disable_surround( bool disable ) { surround_threshold = disable ? 0 : -0x7FFF; }
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inline void Spc_Dsp::set_gain( double v ) { emu_gain = (int) (v * (1 << emu_gain_bits)); }
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inline int Spc_Dsp::read( int i )
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{
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assert( (unsigned) i < register_count );
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return reg [i];
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}
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#endif
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