cog/Frameworks/GME/gme/Ym2413_Emu.cpp

79 lines
1.6 KiB
C++

// Game_Music_Emu $vers. http://www.slack.net/~ant/
#include "Ym2413_Emu.h"
#include "ym2413.h"
Ym2413_Emu::Ym2413_Emu() { opll = 0; }
Ym2413_Emu::~Ym2413_Emu()
{
if ( opll ) ym2413_shutdown( opll );
}
int Ym2413_Emu::set_rate( int sample_rate, int clock_rate )
{
if ( opll )
{
ym2413_shutdown( opll );
opll = 0;
}
opll = ym2413_init( clock_rate, sample_rate, 0 );
if ( !opll )
return 1;
reset();
return 0;
}
void Ym2413_Emu::reset()
{
ym2413_reset_chip( opll );
ym2413_set_mask( opll, 0 );
}
static stream_sample_t* DUMMYBUF[0x02] = {(stream_sample_t*)NULL, (stream_sample_t*)NULL};
void Ym2413_Emu::write( int addr, int data )
{
ym2413_update_one( opll, DUMMYBUF, 0 );
ym2413_write( opll, 0, addr );
ym2413_write( opll, 1, data );
}
void Ym2413_Emu::mute_voices( int mask )
{
ym2413_set_mask( opll, mask );
}
void Ym2413_Emu::run( int pair_count, sample_t* out )
{
SAMP bufMO[ 1024 ];
SAMP bufRO[ 1024 ];
SAMP * buffers[2] = { bufMO, bufRO };
while (pair_count > 0)
{
int todo = pair_count;
if (todo > 1024) todo = 1024;
ym2413_update_one( opll, buffers, todo );
for (int i = 0; i < todo; i++)
{
int output_l, output_r;
int output = bufMO [i];
output += bufRO [i];
output *= 3;
output_l = output + out [0];
output_r = output + out [1];
if ( (short)output_l != output_l ) output_l = 0x7FFF ^ ( output_l >> 31 );
if ( (short)output_r != output_r ) output_r = 0x7FFF ^ ( output_r >> 31 );
out [0] = output_l;
out [1] = output_r;
out += 2;
}
pair_count -= todo;
}
}