a1145a1d04
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30284 a1c6a512-1295-4272-9138-f99709370657
116 lines
2.5 KiB
C
116 lines
2.5 KiB
C
// NES FDS sound chip emulator
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// Game_Music_Emu 0.6-pre
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#ifndef NES_FDS_APU_H
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#define NES_FDS_APU_H
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#include "blargg_common.h"
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#include "blip_buffer.h"
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enum { lfo_base_tempo = 8 };
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enum { fds_osc_count = 1 };
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enum { fds_io_addr = 0x4040 };
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enum { fds_io_size = 0x53 };
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enum { fds_wave_size = 0x40 };
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enum { fds_master_vol_max = 10 };
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enum { fds_vol_max = 0x20 };
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enum { fds_wave_sample_max = 0x3F };
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struct Nes_Fds_Apu {
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unsigned char regs_ [fds_io_size];// last written value to registers
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int lfo_tempo; // normally 8; adjusted by set_tempo()
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int env_delay;
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int env_speed;
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int env_gain;
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int sweep_delay;
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int sweep_speed;
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int sweep_gain;
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int wave_pos;
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int last_amp;
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blip_time_t wave_fract;
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int mod_fract;
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int mod_pos;
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int mod_write_pos;
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unsigned char mod_wave [fds_wave_size];
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// synthesis
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blip_time_t last_time;
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struct Blip_Buffer* output_;
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struct Blip_Synth synth;
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};
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// init
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void Fds_init( struct Nes_Fds_Apu* this );
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// setup
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void Fds_set_tempo( struct Nes_Fds_Apu* this, int t );
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// emulation
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void Fds_reset( struct Nes_Fds_Apu* this );
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static inline void Fds_volume( struct Nes_Fds_Apu* this, int v )
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{
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Synth_volume( &this->synth, (v*14) / 100 / fds_master_vol_max / fds_vol_max / fds_wave_sample_max );
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}
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static inline void Fds_set_output( struct Nes_Fds_Apu* this, int i, struct Blip_Buffer* b )
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{
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#if defined(ROCKBOX)
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(void) i;
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#endif
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assert( (unsigned) i < fds_osc_count );
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this->output_ = b;
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}
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void Fds_run_until( struct Nes_Fds_Apu* this, blip_time_t );
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static inline void Fds_end_frame( struct Nes_Fds_Apu* this, blip_time_t end_time )
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{
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if ( end_time > this->last_time )
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Fds_run_until( this, end_time );
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this->last_time -= end_time;
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assert( this->last_time >= 0 );
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}
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void Fds_write_( struct Nes_Fds_Apu* this, unsigned addr, int data );
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static inline void Fds_write( struct Nes_Fds_Apu* this, blip_time_t time, unsigned addr, int data )
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{
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Fds_run_until( this, time );
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Fds_write_( this, addr, data );
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}
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static inline int Fds_read( struct Nes_Fds_Apu* this, blip_time_t time, unsigned addr )
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{
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Fds_run_until( this, time );
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int result = 0xFF;
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switch ( addr )
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{
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case 0x4090:
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result = this->env_gain;
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break;
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case 0x4092:
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result = this->sweep_gain;
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break;
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default:
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{
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unsigned i = addr - fds_io_addr;
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if ( i < fds_wave_size )
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result = this->regs_ [i];
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}
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}
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return result | 0x40;
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}
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// allow access to registers by absolute address (i.e. 0x4080)
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static inline unsigned char* regs_nes( struct Nes_Fds_Apu* this, unsigned addr ) { return &this->regs_ [addr - fds_io_addr]; }
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#endif
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