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Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius <nils@rockbox.org> Tested-by: Nils Wallménius <nils@rockbox.org>
164 lines
3.3 KiB
C
164 lines
3.3 KiB
C
// Private oscillators used by Nes_Apu
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// Nes_Snd_Emu 0.1.8
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#ifndef NES_OSCS_H
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#define NES_OSCS_H
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#include "blargg_common.h"
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#include "blip_buffer.h"
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#include "nes_cpu.h"
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struct Nes_Apu;
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struct Nes_Osc
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{
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unsigned char regs [4];
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bool reg_written [4];
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struct Blip_Buffer* output;
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int length_counter;// length counter (0 if unused by oscillator)
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int delay; // delay until next (potential) transition
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int last_amp; // last amplitude oscillator was outputting
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};
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void Osc_clock_length( struct Nes_Osc* this, int halt_mask );
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static inline int Osc_period( struct Nes_Osc* this )
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{
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return (this->regs [3] & 7) * 0x100 + (this->regs [2] & 0xFF);
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}
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static inline void Osc_reset( struct Nes_Osc* this )
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{
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this->delay = 0;
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this->last_amp = 0;
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}
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static inline int Osc_update_amp( struct Nes_Osc* this, int amp )
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{
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int delta = amp - this->last_amp;
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this->last_amp = amp;
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return delta;
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}
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// Nes_Square
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enum { negate_flag = 0x08 };
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enum { shift_mask = 0x07 };
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enum { square_phase_range = 8 };
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typedef struct Blip_Synth Synth;
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struct Nes_Square
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{
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struct Nes_Osc osc;
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int envelope;
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int env_delay;
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int phase;
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int sweep_delay;
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Synth* synth; // shared between squares
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};
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static inline void Square_set_synth( struct Nes_Square* this, Synth* s ) { this->synth = s; }
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void Square_clock_sweep( struct Nes_Square* this, int adjust );
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void Square_run( struct Nes_Square* this, nes_time_t, nes_time_t );
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static inline void Square_reset( struct Nes_Square* this )
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{
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this->sweep_delay = 0;
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this->envelope = 0;
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this->env_delay = 0;
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Osc_reset( &this->osc );
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}
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void Square_clock_envelope( struct Nes_Square* this );
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int Square_volume( struct Nes_Square* this );
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// Nes_Triangle
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enum { Triangle_phase_range = 16 };
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struct Nes_Triangle
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{
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struct Nes_Osc osc;
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int phase;
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int linear_counter;
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struct Blip_Synth synth;
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};
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void Triangle_run( struct Nes_Triangle* this, nes_time_t, nes_time_t );
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void Triangle_clock_linear_counter( struct Nes_Triangle* this );
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static inline void Triangle_reset( struct Nes_Triangle* this )
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{
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this->linear_counter = 0;
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this->phase = 1;
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Osc_reset( &this->osc );
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}
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// Nes_Noise
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struct Nes_Noise
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{
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struct Nes_Osc osc;
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int envelope;
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int env_delay;
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int noise;
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struct Blip_Synth synth;
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};
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void Noise_clock_envelope( struct Nes_Noise* this );
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int Noise_volume( struct Nes_Noise* this );
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void Noise_run( struct Nes_Noise* this, nes_time_t, nes_time_t );
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static inline void Noise_reset( struct Nes_Noise* this )
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{
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this->noise = 1 << 14;
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this->envelope = 0;
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this->env_delay = 0;
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Osc_reset( &this->osc );
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}
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// Nes_Dmc
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enum { loop_flag = 0x40 };
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struct Nes_Dmc
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{
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struct Nes_Osc osc;
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int address; // address of next byte to read
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int period;
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int buf;
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int bits_remain;
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int bits;
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bool buf_full;
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bool silence;
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int dac;
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nes_time_t next_irq;
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bool irq_enabled;
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bool irq_flag;
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bool pal_mode;
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bool nonlinear;
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int (*prg_reader)( void*, int ); // needs to be initialized to prg read function
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void* prg_reader_data;
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struct Nes_Apu* apu;
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struct Blip_Synth synth;
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};
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void Dmc_start( struct Nes_Dmc* this );
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void Dmc_write_register( struct Nes_Dmc* this, int, int );
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void Dmc_run( struct Nes_Dmc* this, nes_time_t, nes_time_t );
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void Dmc_recalc_irq( struct Nes_Dmc* this );
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void Dmc_fill_buffer( struct Nes_Dmc* this );
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void Dmc_reset( struct Nes_Dmc* this );
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int Dmc_count_reads( struct Nes_Dmc* this, nes_time_t, nes_time_t* );
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#endif
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