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#include "sms_fm_apu.h"
#include "blargg_source.h"
void Fm_apu_create( struct Sms_Fm_Apu* this )
{
Synth_init( &this->synth );
Ym2413_init( &this->apu );
}
blargg_err_t Fm_apu_init( struct Sms_Fm_Apu* this, int clock_rate, int sample_rate )
{
this->period_ = (blip_time_t) (clock_rate / sample_rate);
CHECK_ALLOC( !Ym2413_set_rate( &this->apu, sample_rate, clock_rate ) );
Fm_apu_set_output( this, 0 );
Fm_apu_volume( this, (int)FP_ONE_VOLUME );
Fm_apu_reset( this );
return 0;
}
void Fm_apu_reset( struct Sms_Fm_Apu* this )
{
this->addr = 0;
this->next_time = 0;
this->last_amp = 0;
Ym2413_reset( &this->apu );
}
void fm_run_until( struct Sms_Fm_Apu* this, blip_time_t end_time );
void Fm_apu_write_data( struct Sms_Fm_Apu* this, blip_time_t time, int data )
{
if ( time > this->next_time )
fm_run_until( this, time );
Ym2413_write( &this->apu, this->addr, data );
}
void fm_run_until( struct Sms_Fm_Apu* this, blip_time_t end_time )
{
assert( end_time > this->next_time );
struct Blip_Buffer* const output = this->output_;
if ( !output )
{
this->next_time = end_time;
return;
}
blip_time_t time = this->next_time;
struct Ym2413_Emu* emu = &this->apu;
do
{
short samples [2];
Ym2413_run( emu, 1, samples );
int amp = (samples [0] + samples [1]) >> 1;
int delta = amp - this->last_amp;
if ( delta )
{
this->last_amp = amp;
Synth_offset_inline( &this->synth, time, delta, output );
}
time += this->period_;
}
while ( time < end_time );
this->next_time = time;
}
void Fm_apu_end_frame( struct Sms_Fm_Apu* this, blip_time_t time )
{
if ( time > this->next_time )
fm_run_until( this, time );
this->next_time -= time;
assert( this->next_time >= 0 );
if ( this->output_ )
Blip_set_modified( this->output_ );
}
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