diff options
Diffstat (limited to 'plugins/gme/game-music-emu-svn/gme/Spc_Dsp.h')
| -rw-r--r-- | plugins/gme/game-music-emu-svn/gme/Spc_Dsp.h | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-svn/gme/Spc_Dsp.h b/plugins/gme/game-music-emu-svn/gme/Spc_Dsp.h new file mode 100644 index 00000000..bc0efe5f --- /dev/null +++ b/plugins/gme/game-music-emu-svn/gme/Spc_Dsp.h @@ -0,0 +1,212 @@ +// Fast SNES SPC-700 DSP emulator (about 3x speed of accurate one) + +// Game_Music_Emu 0.5.5 +#ifndef SPC_DSP_H +#define SPC_DSP_H + +#include "blargg_common.h" + +struct Spc_Dsp { +public: + typedef BOOST::uint8_t uint8_t; + +// Setup + + // Initializes DSP and has it use the 64K RAM provided + void init( void* ram_64k ); + + // Sets destination for output samples. If out is NULL or out_size is 0, + // doesn't generate any. + typedef short sample_t; + void set_output( sample_t* out, int out_size ); + + // Number of samples written to output since it was last set, always + // a multiple of 2. Undefined if more samples were generated than + // output buffer could hold. + int sample_count() const; + +// Emulation + + // Resets DSP to power-on state + void reset(); + + // Emulates pressing reset switch on SNES + void soft_reset(); + + // Reads/writes DSP registers. For accuracy, you must first call spc_run_dsp() + // to catch the DSP up to present. + int read ( int addr ) const; + void write( int addr, int data ); + + // Runs DSP for specified number of clocks (~1024000 per second). Every 32 clocks + // a pair of samples is be generated. + void run( int clock_count ); + +// Sound control + + // Mutes voices corresponding to non-zero bits in mask (overrides VxVOL with 0). + // Reduces emulation accuracy. + enum { voice_count = 8 }; + void mute_voices( int mask ); + + // If true, prevents channels and global volumes from being phase-negated + void disable_surround( bool disable = true ); + +// State + + // Resets DSP and uses supplied values to initialize registers + enum { register_count = 128 }; + void load( uint8_t const regs [register_count] ); + +// DSP register addresses + + // Global registers + enum { + r_mvoll = 0x0C, r_mvolr = 0x1C, + r_evoll = 0x2C, r_evolr = 0x3C, + r_kon = 0x4C, r_koff = 0x5C, + r_flg = 0x6C, r_endx = 0x7C, + r_efb = 0x0D, r_pmon = 0x2D, + r_non = 0x3D, r_eon = 0x4D, + r_dir = 0x5D, r_esa = 0x6D, + r_edl = 0x7D, + r_fir = 0x0F // 8 coefficients at 0x0F, 0x1F ... 0x7F + }; + + // Voice registers + enum { + v_voll = 0x00, v_volr = 0x01, + v_pitchl = 0x02, v_pitchh = 0x03, + v_srcn = 0x04, v_adsr0 = 0x05, + v_adsr1 = 0x06, v_gain = 0x07, + v_envx = 0x08, v_outx = 0x09 + }; + +public: + enum { extra_size = 16 }; + sample_t* extra() { return m.extra; } + sample_t const* out_pos() const { return m.out; } +public: + BLARGG_DISABLE_NOTHROW + + typedef BOOST::int8_t int8_t; + typedef BOOST::int16_t int16_t; + + enum { echo_hist_size = 8 }; + + enum env_mode_t { env_release, env_attack, env_decay, env_sustain }; + enum { brr_buf_size = 12 }; + struct voice_t + { + int buf [brr_buf_size*2];// decoded samples (twice the size to simplify wrap handling) + int* buf_pos; // place in buffer where next samples will be decoded + int interp_pos; // relative fractional position in sample (0x1000 = 1.0) + int brr_addr; // address of current BRR block + int brr_offset; // current decoding offset in BRR block + int kon_delay; // KON delay/current setup phase + env_mode_t env_mode; + int env; // current envelope level + int hidden_env; // used by GAIN mode 7, very obscure quirk + int volume [2]; // copy of volume from DSP registers, with surround disabled + int enabled; // -1 if enabled, 0 if muted + }; +private: + struct state_t + { + uint8_t regs [register_count]; + + // Echo history keeps most recent 8 samples (twice the size to simplify wrap handling) + int echo_hist [echo_hist_size * 2] [2]; + int (*echo_hist_pos) [2]; // &echo_hist [0 to 7] + + int every_other_sample; // toggles every sample + int kon; // KON value when last checked + int noise; + int echo_offset; // offset from ESA in echo buffer + int echo_length; // number of bytes that echo_offset will stop at + int phase; // next clock cycle to run (0-31) + unsigned counters [4]; + + int new_kon; + int t_koff; + + voice_t voices [voice_count]; + + unsigned* counter_select [32]; + + // non-emulation state + uint8_t* ram; // 64K shared RAM between DSP and SMP + int mute_mask; + int surround_threshold; + sample_t* out; + sample_t* out_end; + sample_t* out_begin; + sample_t extra [extra_size]; + }; + state_t m; + + void init_counter(); + void run_counter( int ); + void soft_reset_common(); + void write_outline( int addr, int data ); + void update_voice_vol( int addr ); +}; + +#include <assert.h> + +inline int Spc_Dsp::sample_count() const { return m.out - m.out_begin; } + +inline int Spc_Dsp::read( int addr ) const +{ + assert( (unsigned) addr < register_count ); + return m.regs [addr]; +} + +inline void Spc_Dsp::update_voice_vol( int addr ) +{ + int l = (int8_t) m.regs [addr + v_voll]; + int r = (int8_t) m.regs [addr + v_volr]; + + if ( l * r < m.surround_threshold ) + { + // signs differ, so negate those that are negative + l ^= l >> 7; + r ^= r >> 7; + } + + voice_t& v = m.voices [addr >> 4]; + int enabled = v.enabled; + v.volume [0] = l & enabled; + v.volume [1] = r & enabled; +} + +inline void Spc_Dsp::write( int addr, int data ) +{ + assert( (unsigned) addr < register_count ); + + m.regs [addr] = (uint8_t) data; + int low = addr & 0x0F; + if ( low < 0x2 ) // voice volumes + { + update_voice_vol( low ^ addr ); + } + else if ( low == 0xC ) + { + if ( addr == r_kon ) + m.new_kon = (uint8_t) data; + + if ( addr == r_endx ) // always cleared, regardless of data written + m.regs [r_endx] = 0; + } +} + +inline void Spc_Dsp::disable_surround( bool disable ) +{ + m.surround_threshold = disable ? 0 : -0x4000; +} + +#define SPC_NO_COPY_STATE_FUNCS 1 + +#define SPC_LESS_ACCURATE 1 + +#endif |