1 files changed, 330 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6.0/gme/Sms_Apu.cpp b/plugins/gme/game-music-emu-0.6.0/gme/Sms_Apu.cpp
new file mode 100644
index 00000000..b41fdec4
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+++ b/plugins/gme/game-music-emu-0.6.0/gme/Sms_Apu.cpp
@@ -0,0 +1,330 @@
+// Sms_Snd_Emu 0.1.4. http://www.slack.net/~ant/
+
+#include "Sms_Apu.h"
+
+/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
+can redistribute it and/or modify it under the terms of the GNU Lesser
+General Public License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version. This
+module is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+details. You should have received a copy of the GNU Lesser General Public
+License along with this module; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#include "blargg_source.h"
+
+// Sms_Osc
+
+Sms_Osc::Sms_Osc()
+{
+	output = 0;
+	outputs [0] = 0; // always stays NULL
+	outputs [1] = 0;
+	outputs [2] = 0;
+	outputs [3] = 0;
+}
+
+void Sms_Osc::reset()
+{
+	delay = 0;
+	last_amp = 0;
+	volume = 0;
+	output_select = 3;
+	output = outputs [3];
+}
+
+// Sms_Square
+
+inline void Sms_Square::reset()
+{
+	period = 0;
+	phase = 0;
+	Sms_Osc::reset();
+}
+
+void Sms_Square::run( blip_time_t time, blip_time_t end_time )
+{
+	if ( !volume || period <= 128 )
+	{
+		// ignore 16kHz and higher
+		if ( last_amp )
+		{
+			synth->offset( time, -last_amp, output );
+			last_amp = 0;
+		}
+		time += delay;
+		if ( !period )
+		{
+			time = end_time;
+		}
+		else if ( time < end_time )
+		{
+			// keep calculating phase
+			int count = (end_time - time + period - 1) / period;
+			phase = (phase + count) & 1;
+			time += count * period;
+		}
+	}
+	else
+	{
+		int amp = phase ? volume : -volume;
+		{
+			int delta = amp - last_amp;
+			if ( delta )
+			{
+				last_amp = amp;
+				synth->offset( time, delta, output );
+			}
+		}
+		
+		time += delay;
+		if ( time < end_time )
+		{
+			Blip_Buffer* const output = this->output;
+			int delta = amp * 2;
+			do
+			{
+				delta = -delta;
+				synth->offset_inline( time, delta, output );
+				time += period;
+				phase ^= 1;
+			}
+			while ( time < end_time );
+			this->last_amp = phase ? volume : -volume;
+		}
+	}
+	delay = time - end_time;
+}
+
+// Sms_Noise
+
+static int const noise_periods [3] = { 0x100, 0x200, 0x400 };
+
+inline void Sms_Noise::reset()
+{
+	period = &noise_periods [0];
+	shifter = 0x8000;
+	feedback = 0x9000;
+	Sms_Osc::reset();
+}
+
+void Sms_Noise::run( blip_time_t time, blip_time_t end_time )
+{
+	int amp = volume;
+	if ( shifter & 1 )
+		amp = -amp;
+	
+	{
+		int delta = amp - last_amp;
+		if ( delta )
+		{
+			last_amp = amp;
+			synth.offset( time, delta, output );
+		}
+	}
+	
+	time += delay;
+	if ( !volume )
+		time = end_time;
+	
+	if ( time < end_time )
+	{
+		Blip_Buffer* const output = this->output;
+		unsigned shifter = this->shifter;
+		int delta = amp * 2;
+		int period = *this->period * 2;
+		if ( !period )
+			period = 16;
+		
+		do
+		{
+			int changed = shifter + 1;
+			shifter = (feedback & -(shifter & 1)) ^ (shifter >> 1);
+			if ( changed & 2 ) // true if bits 0 and 1 differ
+			{
+				delta = -delta;
+				synth.offset_inline( time, delta, output );
+			}
+			time += period;
+		}
+		while ( time < end_time );
+		
+		this->shifter = shifter;
+		this->last_amp = delta >> 1;
+	}
+	delay = time - end_time;
+}
+
+// Sms_Apu
+
+Sms_Apu::Sms_Apu()
+{
+	for ( int i = 0; i < 3; i++ )
+	{
+		squares [i].synth = &square_synth;
+		oscs [i] = &squares [i];
+	}
+	oscs [3] = &noise;
+	
+	volume( 1.0 );
+	reset();
+}
+
+Sms_Apu::~Sms_Apu()
+{
+}
+
+void Sms_Apu::volume( double vol )
+{
+	vol *= 0.85 / (osc_count * 64 * 2);
+	square_synth.volume( vol );
+	noise.synth.volume( vol );
+}
+
+void Sms_Apu::treble_eq( const blip_eq_t& eq )
+{
+	square_synth.treble_eq( eq );
+	noise.synth.treble_eq( eq );
+}
+
+void Sms_Apu::osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right )
+{
+	require( (unsigned) index < osc_count );
+	require( (center && left && right) || (!center && !left && !right) );
+	Sms_Osc& osc = *oscs [index];
+	osc.outputs [1] = right;
+	osc.outputs [2] = left;
+	osc.outputs [3] = center;
+	osc.output = osc.outputs [osc.output_select];
+}
+
+void Sms_Apu::output( Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right )
+{
+	for ( int i = 0; i < osc_count; i++ )
+		osc_output( i, center, left, right );
+}
+
+void Sms_Apu::reset( unsigned feedback, int noise_width )
+{
+	last_time = 0;
+	latch = 0;
+	
+	if ( !feedback || !noise_width )
+	{
+		feedback = 0x0009;
+		noise_width = 16;
+	}
+	// convert to "Galios configuration"
+	looped_feedback = 1 << (noise_width - 1);
+	noise_feedback  = 0;
+	while ( noise_width-- )
+	{
+		noise_feedback = (noise_feedback << 1) | (feedback & 1);
+		feedback >>= 1;
+	}
+	
+	squares [0].reset();
+	squares [1].reset();
+	squares [2].reset();
+	noise.reset();
+}
+
+void Sms_Apu::run_until( blip_time_t end_time )
+{
+	require( end_time >= last_time ); // end_time must not be before previous time
+	
+	if ( end_time > last_time )
+	{
+		// run oscillators
+		for ( int i = 0; i < osc_count; ++i )
+		{
+			Sms_Osc& osc = *oscs [i];
+			if ( osc.output )
+			{
+				osc.output->set_modified();
+				if ( i < 3 )
+					squares [i].run( last_time, end_time );
+				else
+					noise.run( last_time, end_time );
+			}
+		}
+		
+		last_time = end_time;
+	}
+}
+
+void Sms_Apu::end_frame( blip_time_t end_time )
+{
+	if ( end_time > last_time )
+		run_until( end_time );
+	
+	assert( last_time >= end_time );
+	last_time -= end_time;
+}
+
+void Sms_Apu::write_ggstereo( blip_time_t time, int data )
+{
+	require( (unsigned) data <= 0xFF );
+	
+	run_until( time );
+	
+	for ( int i = 0; i < osc_count; i++ )
+	{
+		Sms_Osc& osc = *oscs [i];
+		int flags = data >> i;
+		Blip_Buffer* old_output = osc.output;
+		osc.output_select = (flags >> 3 & 2) | (flags & 1);
+		osc.output = osc.outputs [osc.output_select];
+		if ( osc.output != old_output && osc.last_amp )
+		{
+			if ( old_output )
+			{
+				old_output->set_modified();
+				square_synth.offset( time, -osc.last_amp, old_output );
+			}
+			osc.last_amp = 0;
+		}
+	}
+}
+
+// volumes [i] = 64 * pow( 1.26, 15 - i ) / pow( 1.26, 15 )
+static unsigned char const volumes [16] = {
+	64, 50, 39, 31, 24, 19, 15, 12, 9, 7, 5, 4, 3, 2, 1, 0
+};
+
+void Sms_Apu::write_data( blip_time_t time, int data )
+{
+	require( (unsigned) data <= 0xFF );
+	
+	run_until( time );
+	
+	if ( data & 0x80 )
+		latch = data;
+	
+	int index = (latch >> 5) & 3;
+	if ( latch & 0x10 )
+	{
+		oscs [index]->volume = volumes [data & 15];
+	}
+	else if ( index < 3 )
+	{
+		Sms_Square& sq = squares [index];
+		if ( data & 0x80 )
+			sq.period = (sq.period & 0xFF00) | (data << 4 & 0x00FF);
+		else
+			sq.period = (sq.period & 0x00FF) | (data << 8 & 0x3F00);
+	}
+	else
+	{
+		int select = data & 3;
+		if ( select < 3 )
+			noise.period = &noise_periods [select];
+		else
+			noise.period = &squares [2].period;
+		
+		noise.feedback = (data & 0x04) ? noise_feedback : looped_feedback;
+		noise.shifter = 0x8000;
+	}
+}