void Stereo_Mixer::mix_stereo( blip_sample_t* out_, int count )
{
blip_sample_t* BLIP_RESTRICT out = out_ + count * stereo;
// do left + center and right + center separately to reduce register load
Tracked_Blip_Buffer* const* buf = &bufs [2];
while ( true ) // loop runs twice
{
--buf;
--out;
int const bass = BLIP_READER_BASS( *bufs [2] );
BLIP_READER_BEGIN( side, **buf );
BLIP_READER_BEGIN( center, *bufs [2] );
BLIP_READER_ADJ_( side, samples_read );
BLIP_READER_ADJ_( center, samples_read );
int offset = -count;
do
{
blargg_long s = BLIP_READER_READ_RAW( center ) + BLIP_READER_READ_RAW( side );
s >>= blip_sample_bits - 16;
BLIP_READER_NEXT_IDX_( side, bass, offset );
BLIP_READER_NEXT_IDX_( center, bass, offset );
BLIP_CLAMP( s, s );
++offset; // before write since out is decremented to slightly before end
out [offset * stereo] = (blip_sample_t) s;
}
while ( offset );
BLIP_READER_END( side, **buf );
if ( buf != bufs )
continue;
// only end center once
BLIP_READER_END( center, *bufs [2] );
break;
}
}
void Stereo_Mixer::mix_mono( blip_sample_t* out_, int count )
{
int const bass = BLIP_READER_BASS( *bufs [2] );
BLIP_READER_BEGIN( center, *bufs [2] );
BLIP_READER_ADJ_( center, samples_read );
typedef blip_sample_t stereo_blip_sample_t [stereo];
stereo_blip_sample_t* BLIP_RESTRICT out = (stereo_blip_sample_t*) out_ + count;
int offset = -count;
do
{
blargg_long s = BLIP_READER_READ( center );
BLIP_READER_NEXT_IDX_( center, bass, offset );
BLIP_CLAMP( s, s );
out [offset] [0] = (blip_sample_t) s;
out [offset] [1] = (blip_sample_t) s;
}
while ( ++offset );
BLIP_READER_END( center, *bufs [2] );
}
void Effects_Buffer::mix_effects( blip_sample_t* out_, int pair_count )
{
typedef fixed_t stereo_fixed_t [stereo];
// add channels with echo, do echo, add channels without echo, then convert to 16-bit and output
int echo_phase = 1;
do
{
// mix any modified buffers
{
buf_t* buf = bufs;
int bufs_remain = bufs_size;
do
{
if ( buf->non_silent() && ( buf->echo == (bool)echo_phase ) )
{
stereo_fixed_t* BLIP_RESTRICT out = (stereo_fixed_t*) &echo [echo_pos];
int const bass = BLIP_READER_BASS( *buf );
BLIP_READER_BEGIN( in, *buf );
BLIP_READER_ADJ_( in, mixer.samples_read );
fixed_t const vol_0 = buf->vol [0];
fixed_t const vol_1 = buf->vol [1];
int count = unsigned (echo_size - echo_pos) / stereo;
int remain = pair_count;
if ( count > remain )
count = remain;
do
{
remain -= count;
BLIP_READER_ADJ_( in, count );
out += count;
int offset = -count;
do
{
fixed_t s = BLIP_READER_READ( in );
BLIP_READER_NEXT_IDX_( in, bass, offset );
out [offset] [0] += s * vol_0;
out [offset] [1] += s * vol_1;
}
while ( ++offset );
out = (stereo_fixed_t*) echo.begin();
count = remain;
}
while ( remain );
BLIP_READER_END( in, *buf );
}
buf++;
}
while ( --bufs_remain );
}
// add echo
if ( echo_phase && !no_echo )
{
fixed_t const feedback = s.feedback;
fixed_t const treble = s.treble;
int i = 1;
do
{
fixed_t low_pass = s.low_pass [i];
fixed_t* echo_end = &echo [echo_size + i];
fixed_t const* BLIP_RESTRICT in_pos = &echo [echo_pos + i];
blargg_long out_offset = echo_pos + i + s.delay [i];
if ( out_offset >= echo_size )
out_offset -= echo_size;
assert( out_offset < echo_size );
fixed_t* BLIP_RESTRICT out_pos = &echo [out_offset];
// break into up to three chunks to avoid having to handle wrap-around
// in middle of core loop
int remain = pair_count;
do
{
fixed_t const* pos = in_pos;
if ( pos < out_pos )
pos = out_pos;
int count = blargg_ulong ((char*) echo_end - (char const*) pos) /
unsigned (stereo * sizeof (fixed_t));
if ( count > remain )
count = remain;
remain -= count;
in_pos += count * stereo;
out_pos += count * stereo;
int offset = -count;
do
{
low_pass += FROM_FIXED( in_pos [offset * stereo] - low_pass ) * treble;
out_pos [offset * stereo] = FROM_FIXED( low_pass ) * feedback;
}
while ( ++offset );
if ( in_pos >= echo_end ) in_pos -= echo_size;
if ( out_pos >= echo_end ) out_pos -= echo_size;
}
while ( remain );
s.low_pass [i] = low_pass;
}
while ( --i >= 0 );
}
}
while ( --echo_phase >= 0 );
// clamp to 16 bits
{
stereo_fixed_t const* BLIP_RESTRICT in = (stereo_fixed_t*) &echo [echo_pos];
typedef blip_sample_t stereo_blip_sample_t [stereo];
stereo_blip_sample_t* BLIP_RESTRICT out = (stereo_blip_sample_t*) out_;
int count = unsigned (echo_size - echo_pos) / (unsigned) stereo;
int remain = pair_count;
if ( count > remain )
count = remain;
do
{
remain -= count;
in += count;
out += count;
int offset = -count;
do
{
fixed_t in_0 = FROM_FIXED( in [offset] [0] );
fixed_t in_1 = FROM_FIXED( in [offset] [1] );
BLIP_CLAMP( in_0, in_0 );
out [offset] [0] = (blip_sample_t) in_0;
BLIP_CLAMP( in_1, in_1 );
out [offset] [1] = (blip_sample_t) in_1;
}
while ( ++offset );
in = (stereo_fixed_t*) echo.begin();
count = remain;
}
while ( remain );
}
}