a1145a1d04
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30284 a1c6a512-1295-4272-9138-f99709370657
82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
#include "sms_fm_apu.h"
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#include "blargg_source.h"
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void Fm_apu_create( struct Sms_Fm_Apu* this )
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{
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Synth_init( &this->synth );
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Ym2413_init( &this->apu );
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}
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blargg_err_t Fm_apu_init( struct Sms_Fm_Apu* this, int clock_rate, int sample_rate )
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{
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this->period_ = (blip_time_t) (clock_rate / sample_rate);
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CHECK_ALLOC( !Ym2413_set_rate( &this->apu, sample_rate, clock_rate ) );
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Fm_apu_set_output( this, 0 );
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Fm_apu_volume( this, (int)FP_ONE_VOLUME );
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Fm_apu_reset( this );
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return 0;
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}
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void Fm_apu_reset( struct Sms_Fm_Apu* this )
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{
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this->addr = 0;
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this->next_time = 0;
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this->last_amp = 0;
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Ym2413_reset( &this->apu );
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}
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void fm_run_until( struct Sms_Fm_Apu* this, blip_time_t end_time );
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void Fm_apu_write_data( struct Sms_Fm_Apu* this, blip_time_t time, int data )
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{
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if ( time > this->next_time )
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fm_run_until( this, time );
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Ym2413_write( &this->apu, this->addr, data );
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}
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void fm_run_until( struct Sms_Fm_Apu* this, blip_time_t end_time )
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{
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assert( end_time > this->next_time );
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struct Blip_Buffer* const output = this->output_;
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if ( !output )
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{
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this->next_time = end_time;
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return;
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}
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blip_time_t time = this->next_time;
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struct Ym2413_Emu* emu = &this->apu;
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do
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{
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short samples [2];
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Ym2413_run( emu, 1, samples );
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int amp = (samples [0] + samples [1]) >> 1;
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int delta = amp - this->last_amp;
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if ( delta )
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{
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this->last_amp = amp;
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Synth_offset_inline( &this->synth, time, delta, output );
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}
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time += this->period_;
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}
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while ( time < end_time );
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this->next_time = time;
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}
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void Fm_apu_end_frame( struct Sms_Fm_Apu* this, blip_time_t time )
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{
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if ( time > this->next_time )
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fm_run_until( this, time );
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this->next_time -= time;
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assert( this->next_time >= 0 );
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if ( this->output_ )
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Blip_set_modified( this->output_ );
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}
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