1 files changed, 124 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6pre/gme/Kss_Scc_Apu.cpp b/plugins/gme/game-music-emu-0.6pre/gme/Kss_Scc_Apu.cpp
new file mode 100644
index 00000000..18625894
--- /dev/null
+++ b/plugins/gme/game-music-emu-0.6pre/gme/Kss_Scc_Apu.cpp
@@ -0,0 +1,124 @@
+// Game_Music_Emu 0.6-pre. http://www.slack.net/~ant/
+
+#include "Kss_Scc_Apu.h"
+
+/* Copyright (C) 2006-2008 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"
+
+// Tones above this frequency are treated as disabled tone at half volume.
+// Power of two is more efficient (avoids division).
+int const inaudible_freq = 16384;
+
+int const wave_size = 0x20;
+
+void Scc_Apu::set_output( Blip_Buffer* buf )
+{
+	for ( int i = 0; i < osc_count; ++i )
+		set_output( i, buf );
+}
+
+void Scc_Apu::volume( double v )
+{
+	synth.volume( 0.43 / osc_count / amp_range * v );
+}
+
+void Scc_Apu::reset()
+{
+	last_time = 0;
+
+	for ( int i = osc_count; --i >= 0; )
+		memset( &oscs [i], 0, offsetof (osc_t,output) );
+
+	memset( regs, 0, sizeof regs );
+}
+
+Scc_Apu::Scc_Apu()
+{
+	set_output( NULL );
+	volume( 1.0 );
+	reset();
+}
+
+void Scc_Apu::run_until( blip_time_t end_time )
+{
+	for ( int index = 0; index < osc_count; index++ )
+	{
+		osc_t& osc = oscs [index];
+
+		Blip_Buffer* const output = osc.output;
+		if ( !output )
+			continue;
+
+		blip_time_t period = (regs [0xA0 + index * 2 + 1] & 0x0F) * 0x100 +
+				regs [0xA0 + index * 2] + 1;
+		int volume = 0;
+		if ( regs [0xAF] & (1 << index) )
+		{
+			blip_time_t inaudible_period = (unsigned) (output->clock_rate() +
+					inaudible_freq * 32) / (unsigned) (inaudible_freq * 16);
+			if ( period > inaudible_period )
+				volume = (regs [0xAA + index] & 0x0F) * (amp_range / 256 / 15);
+		}
+
+		BOOST::int8_t const* wave = (BOOST::int8_t*) regs + index * wave_size;
+		/*if ( index == osc_count - 1 )
+			wave -= wave_size; // last two oscs share same wave RAM*/
+
+		{
+			int delta = wave [osc.phase] * volume - osc.last_amp;
+			if ( delta )
+			{
+				osc.last_amp += delta;
+				output->set_modified();
+				synth.offset( last_time, delta, output );
+			}
+		}
+
+		blip_time_t time = last_time + osc.delay;
+		if ( time < end_time )
+		{
+			int phase = osc.phase;
+			if ( !volume )
+			{
+				// maintain phase
+				int count = (end_time - time + period - 1) / period;
+				phase += count; // will be masked below
+				time  += count * period;
+			}
+			else
+			{
+				int last_wave = wave [phase];
+				phase = (phase + 1) & (wave_size - 1); // pre-advance for optimal inner loop
+				do
+				{
+					int delta = wave [phase] - last_wave;
+					phase = (phase + 1) & (wave_size - 1);
+					if ( delta )
+					{
+						last_wave += delta;
+						synth.offset_inline( time, delta * volume, output );
+					}
+					time += period;
+				}
+				while ( time < end_time );
+
+				osc.last_amp = last_wave * volume;
+				output->set_modified();
+				phase--; // undo pre-advance
+			}
+			osc.phase = phase & (wave_size - 1);
+		}
+		osc.delay = time - end_time;
+	}
+	last_time = end_time;
+}